hydr
hydr — combining form
1. a prefix that means 'water' or 'relating to water' — used to form words dealing
a prefix that means 'water' or 'relating to water' — used to form words dealing with water as a substance, body of water, or the movement of water.
A fire hydrant provides water for firefighters in an emergency.
hydr- in hydrant = water supply device
Sofia is studying hydrology, the science of how water moves through the ground and rivers.
hydrology = study of water
The hydroelectric dam uses flowing water to generate electricity for nearby towns.
After three days without water, the doctor gave the patient IV fluids to rehydrate her body.
Marine biologists mapped the underwater hydrothermal vents where hot water rises from the ocean floor.
- aqua-
Latin-based equivalent used in fewer technical English words (e.g., aquatic, aquarium)
文法句型
hydr- + noun
hydro- + adjective/noun
用法筆記
This is the most common sense of the combining form. It appears as hydr- before consonants and hydro- before vowels (e.g., hydroelectric, not hydrelectric).
常見錯誤
2. a prefix that means 'liquid' or 'fluid' — used mainly in technical words about t
a prefix that means 'liquid' or 'fluid' — used mainly in technical words about the behaviour of liquids under pressure or in motion.
Hydraulic presses use liquid under high pressure to shape metal sheets.
hydraulic = operated by liquid pressure
A car's braking system relies on hydraulics to transfer force from the pedal to the wheels.
hydraulics = liquid-based mechanical system
The lab technician studied hydrolysis, the chemical breakdown of a compound caused by a reaction with a liquid.
Hydrostatic pressure measures the force that a still liquid exerts on the walls of its container.
- fluid-
less common as a prefix; 'fluidic' is a related term in engineering
文法句型
hydr- + noun/adjective
hydro- + noun/adjective
用法筆記
Distinguish from sense 1 (WATER): sense 2 refers to any liquid or fluid regardless of chemical composition, while sense 1 is restricted to water. Hydraulic systems use oil, not water, yet the prefix still applies.
常見錯誤
3. a prefix that means 'hydrogen' or 'containing hydrogen' — used in chemistry to n
a prefix that means 'hydrogen' or 'containing hydrogen' — used in chemistry to name compounds or reactions that involve the element hydrogen.
Methane is the simplest hydrocarbon, made of one carbon atom and four hydrogen atoms.
hydrocarbon = compound of hydrogen and carbon
Dr. Chen studied how hydrogenation turns liquid vegetable oils into solid margarine.
hydrogenation = adding hydrogen to a compound
A hydrogen fuel cell combines hydrogen gas with oxygen to produce electricity and water.
Hydrochloric acid in the stomach contains hydrogen and chlorine and helps break down food.
Sodium hydroxide is a strong base used in cleaning products and soap-making.
文法句型
hydro- + noun/adjective (chemical terms)
用法筆記
In chemical terms, hydro- before a halogen name means 'containing hydrogen and that halogen' (e.g., hydrobromic acid = HBr). Before a non-metal name it often signals a binary acid (e.g., hydrofluoric acid = HF).
常見錯誤
4. a prefix that means 'relating to the Hydra genus of cnidarians or similar small
a prefix that means 'relating to the Hydra genus of cnidarians or similar small marine animals' — used in animal classification terms.
A hydroid colony looks like a tiny plant but is actually a group of small marine animals related to jellyfish.
hydroid = animal from the Hydra group
The marine biology class examined hydrozoans under the microscope to see their stinging cells.
hydrozoan = class of Hydroid-related animals
Freshwater hydra are tiny tube-shaped animals that can regrow an entire body from a small piece.
文法句型
hydro- + noun (zoological terms)
用法筆記
This is a highly specialised zoological sense. The word hydra (without combining-form hyphen) is the common noun for the freshwater creature; the combining form hydro- appears in formal taxonomic names.