solids
solids — adjective
- solidspositive
- more solidscomparative
- most solidssuperlative
1. describing a material or object that keeps its own shape because it does not ben
describing a material or object that keeps its own shape because it does not bend or change form when you press or squeeze it.
The ice on the lake was solid enough for people to walk on safely.
describing frozen water as a solid surface
Sari sat on the solid wooden bench near the fountain, glad it did not wobble.
The builders used solid concrete blocks for the school's foundation so it would not shift over time.
collocation: solid concrete / solid wood / solid stone
A tofu block looks solid but breaks apart quite easily when you cut it.
- solid ground
- solid surface
- solid wood
- solid concrete
- solid rock
Usage Note
This sense contrasts with soft, liquid, or flexible materials. A solid object does not change shape when touched, but it may break under enough force.
Common Mistakes
2. existing in a physical state that keeps a fixed shape and volume, unlike a liqui
existing in a physical state that keeps a fixed shape and volume, unlike a liquid that flows or a gas that spreads out in the air.
Water becomes solid when the temperature drops below zero degrees Celsius.
science context: states of matter
In science class, Leo learned that a rock is solid but steam is a gas.
Butter is solid when it comes out of the fridge, but it melts into a liquid in a warm pan.
Paraffin wax is a solid at room temperature but turns into a clear liquid when you heat it up.
state change of a familiar household substance
- solid state
- solid form
- solid matter
- solid substance
- frozen
restricted to substances that freeze; only applies when the solid is formed by cooling a liquid
Usage Note
This is the scientific or general-descriptive use of 'solid' as one of the three basic states of matter. It is different from sense 1 (hard/firm) — a soft solid like clay is still a solid, not a liquid or gas, even though it can be pressed into a new shape.
Common Mistakes
3. strong, dependable, or well-made, so that you feel confident trusting it as a ba
strong, dependable, or well-made, so that you feel confident trusting it as a basis for decisions, opinions, or physical support.
Hyun has built a solid reputation as a fair and honest manager over the past ten years.
collocation: solid reputation
The company presented a solid business plan that convinced the bank to approve the loan.
Ada gave her students solid advice about how to prepare for the exam without panicking.
The old wooden bridge is surprisingly solid and can support heavy farm vehicles.
physical sense of strong construction
- solid reputation
- solid evidence
- solid plan
- solid advice
- solid foundation
- solid understanding
- reliable
focuses on trustworthiness; a reliable person does what they promise
- strong
more general; a strong argument is persuasive, while a solid argument is well-founded and dependable
- sound
formal; 'sound advice' is based on good judgment and careful thought
- dependable
can be counted on in difficult situations; a dependable friend never lets you down
- weak
lacks strength or evidence; a weak argument is easy to disprove
- unreliable
cannot be trusted; unreliable information leads to wrong conclusions
Usage Note
This sense covers both physical durability ('a solid table') and abstract reliability ('solid evidence', 'solid argument'). The subject is typically a plan, reputation, relationship, evidence, or piece of advice.
Common Mistakes
4. having no empty space or gaps inside an object; filled completely through the wh
having no empty space or gaps inside an object; filled completely through the whole body of the thing.
The old tree trunk looked solid, but inside it was completely empty and rotten.
contrast between solid (filled) and hollow (empty)
Rafael prefers a solid chocolate egg over a hollow one because it feels heavier and richer.
The wall was built with solid bricks, not the lightweight hollow kind used for inside rooms.
collocation: solid brick vs hollow brick
Eli tapped the metal pipe and heard a ringing sound, which meant it was hollow and not solid.
- solid brick
- solid bar
- solid cylinder
- solid ball
- dense
more scientific; 'dense' emphasises mass per volume rather than absence of holes
Usage Note
Frequently used in contrast with 'hollow' or 'filled with air'. Objects can be described as 'solid' in this sense even if they contain small bubbles, as long as there is no large empty cavity.
5. describing food that is eaten in a firm, non-liquid form, especially when a baby
describing food that is eaten in a firm, non-liquid form, especially when a baby starts eating things other than milk, or when a sick person returns to normal eating.
The doctor said the patient could start eating solid food again after two days of soup.
medical/health context
Dylan's baby just turned six months old and is beginning to try solid foods like mashed banana.
After the surgery, Lakshmi could only drink liquids for a week before moving to soft solid foods.
The hospital menu offers both liquid meals and solid options for patients at different recovery stages.
contrast: liquid meals vs solid options
- solid food
- solid meal
- solid diet
- eat solid foods
- regular food
less common; 'regular food' contrasts with baby food or hospital liquids
Usage Note
Almost always used in contrast with 'liquid' or in the phrase 'solid food(s)' as a category. This sense is closely related to noun sense 3 and is common in medical, parenting, and dietary contexts.
Common Mistakes
6. happening or lasting without any breaks or pauses for a long period of time.
happening or lasting without any breaks or pauses for a long period of time.
Mathieu studied for three solid hours without checking his phone once.
pattern: [number] + solid + [time unit]
The rain fell for three solid days without stopping, flooding the streets of the old town.
After a solid week of rain, the streets in the old part of town were completely flooded.
Sari drove for a solid ten hours to reach her grandmother's house before dark.
- solid hour
- solid day
- solid week
- solid year
- solid block of time
- non-stop
less formal; 'a non-stop flight' continues without any scheduled stops
- uninterrupted
more formal; 'uninterrupted sleep' means no one woke you up
- continuous
neutral register; 'continuous rainfall' fell without stopping
- broken
interrupted by pauses; broken sleep means you woke up several times
Usage Note
Always appears before a time expression: 'a solid [time period]' or '[number] solid [time unit]'. The meaning is 'non-stop for that entire duration'. Do not confuse with sense 3 — 'solid week of work' means continuous work for a week, not high-quality work.
Common Mistakes
7. describing a metal made of one single substance without other metals mixed in, o
describing a metal made of one single substance without other metals mixed in, or a colour that is the same all over with no pattern or second colour.
Ingrid bought a necklace made of solid silver, not just silver-plated copper.
collocation: solid silver / solid gold
The artist painted the wall in a solid blue colour with no lines or decorations.
Adisa chose a solid gold ring for the wedding because it would last longer than gold-plated jewellery.
The company logo uses a solid red circle without any outline or text inside it.
solid colour meaning uniform and unbroken
- solid gold
- solid silver
- solid colour
- solid copper
- pure
more general; 'pure gold' can mean 24-carat, while 'solid gold' emphasises the object is gold all through, not just on the surface
- unmixed
describes a colour or substance that has no other colour or ingredient
- unbroken colour
specific to surface colour; a solid colour has no pattern or texture
- mixed
contains different substances; mixed metals contain several types of ore blended together
Usage Note
When describing metals, 'solid' means the entire object is made of the same metal throughout, not just coated. For colours, 'solid' means a single uniform shade across the whole surface.
Common Mistakes
8. relating to objects or shapes that have length, width, and height, rather than f
relating to objects or shapes that have length, width, and height, rather than flat two-dimensional figures.
In geometry class, the students learned to calculate the volume of solid shapes like cubes and spheres.
math context: solid shapes = 3D figures
A cylinder is a solid figure because it has a circular base on top and bottom with height between them.
Eli used modelling clay to build a solid pyramid for his school project on ancient Egypt.
The maths textbook shows both flat shapes and solid figures with their surface areas and volumes.
contrast: flat shapes vs solid figures
- solid figure
- solid shape
- solid geometry
- solid object
- three-dimensional
more technical and explicit; 'three-dimensional shapes include cubes, spheres, and pyramids'
- volumetric
very technical; rarely used in everyday language
- flat
having only two dimensions; a flat drawing on paper is not a solid shape
- two-dimensional
having only length and width, no height; a square is two-dimensional
Usage Note
Mainly used in mathematics and geometry. A 'solid figure' or 'solid shape' occupies three-dimensional space, unlike a 'plane figure' (2D) such as a triangle or circle. This sense is distinct from the general 'hard/firm' meaning.
solids — adverb
1. in a way that is firm, strong, or complete; without any weakness or gaps.
in a way that is firm, strong, or complete; without any weakness or gaps.
The shelves were fixed solidly to the wall so that nothing would fall off during an earthquake.
adverb form 'solidly' modifying a verb
Leo can speak Spanish solidly after living in Madrid for three years.
The archery team performed solidly in every round, hitting the centre of the target more often than their rivals.
Lakshmi stood solidly behind her decision to move abroad, even when her family had doubts.
figurative use: stand solidly behind = firmly support
- solidly built
- solidly fixed
- stand solidly
- play solidly
- solidly behind
Usage Note
The adverb 'solidly' is the word used in this sense, not 'solid'. It can modify verbs of physical attachment (fix, build, stand) as well as abstract actions (support, perform, argue). The comparative form is 'more solidly'.
Common Mistakes
solids — noun
- solidssingular
- solidsesplural
1. matter that exists in a firm state with a fixed shape, rather than flowing like
matter that exists in a firm state with a fixed shape, rather than flowing like a liquid or spreading freely like a gas.
When you freeze water, it changes from a liquid into a solid that you can hold in your hand.
state change: liquid → solid
The chemist explained that iron is a solid at room temperature, while mercury is a liquid.
The waste treatment plant separates solids from the water before releasing it into the river.
collocation: separate solids from liquids
Ingrid poured the liquid through a filter and watched the small solids collect on top of the paper.
- solid waste
- solid particles
- solid matter
- solid fuel
- solid state
Usage Note
As a countable noun (a solid / solids), it refers to individual items or types of solid matter. As an uncountable noun, it refers to the category of solid substances in general ('solid turns to liquid when heated'). In scientific contexts, 'solids' is one of the three states of matter.
Common Mistakes
2. a shape that has length, width, and height — like cubes, spheres and pyramids —
a shape that has length, width, and height — like cubes, spheres and pyramids — rather than being flat like a square or circle drawn on paper.
The teacher asked the children to bring empty boxes and tubes to build different solids for the art project.
classroom context: building solids from everyday objects
A cube and a sphere are both geometric solids, but a triangle drawn on paper is not.
In geometry class, Mei-Lin drew a rectangular prism and labelled each face, edge, and corner of the solid.
Salma counted the edges and corners on each solid she built with her geometry set at school.
- geometric solid
- solid figure
- regular solid
- Platonic solid
- three-dimensional figure
more formal mathematical term; used in textbooks
- solid figure
synonymous; 'solid figure' is slightly more precise in geometry lessons
- plane figure
a flat two-dimensional shape like a triangle or circle
Usage Note
In mathematics, 'solids' (plural) often refers to a category of 3D figures studied as a group. The singular 'solid' refers to one such shape. This sense is distinct from noun sense 1 (physical matter) — here the focus is on the geometric form, not the material.
3. food that is firm and needs to be chewed, rather than being in liquid form like
food that is firm and needs to be chewed, rather than being in liquid form like soup or juice.
The baby's mother started introducing solids when he was six months old, beginning with mashed vegetables.
baby weaning context
After two days of only drinking broth, the patient was eager to eat real solids again.
Eli packed both liquids and solids for the camping trip — juice boxes for drinks and granola bars to eat.
contrast: liquids vs solids in a packing context
The paediatrician gave the parents a chart showing which solids are safe for babies under twelve months.
- eat solids
- start solids
- introduce solids
- tolerate solids
- solids and liquids
- solid food
the full phrase; 'solids' is a shortened form used in medical and parenting contexts
- liquids
drinks and other fluid foods; patients on a liquid diet cannot have solids
Usage Note
Used mainly in the plural 'solids' to refer to the category of non-liquid foods. Commonly appears in medical advice about babies starting to eat, or in dietary guidelines for patients recovering from surgery. 'Solids' in this sense is always plural — you cannot say 'a solid' to mean a piece of food.
Common Mistakes
Word family
- solidadjectiveA2
- solidnounB1
- solidlyadverbB2
- soliditynounC1
- solidifyverbB2
- solidificationnounC2
- consolidateverbB2
- consolidationnounC1
Synonym discussion
Sense: adjective/3
All four words describe something trustworthy, but they differ in emphasis. 'Reliable' focuses on consistency over time — a reliable car starts every morning without fail. 'Strong' is the broadest term; a strong argument is forceful and persuasive, though not necessarily well-grounded. 'Sound' is more formal and intellectual — sound judgment comes from careful reasoning, not emotion. 'Dependable' is close to reliable but feels more personal; a dependable friend will help you even when it is inconvenient. 'Solid' combines the best of these qualities: a solid plan is both well-constructed (like 'sound') and consistently workable (like 'reliable'). For example: 'The police built a solid case based on DNA evidence, not just witness statements.' And: 'She gave him a solid handshake that showed she meant business.'
Common collocations
Nouns
- solid ground
- solid foundation
- solid surface
- solid evidence
- solid waste
Adverbs
- completely solid
- perfectly solid
- fairly solid
- reasonably solid
Phrases
- solid as a rock
- on solid ground
Prepositions
- solid as (a rock)
- solid of
Etymology
The word 'solid' comes from Latin 'solidus', meaning 'firm, whole, unbroken'. It entered English through Old French 'solide' in the 1300s. The noun use for 'a three-dimensional body' developed in geometry and science during the 1600s, while the adverb form 'solidly' appeared around the same time. The sense of 'reliable, well-made' grew from the physical meaning over the 1700s and 1800s.
First known use
14th century
14th century, in the meaning defined at sense 1a Noun