trichomes

trichomes — noun

1. tiny hair-like or scale-like structures that grow from the outer surface of a pl

1.nounC2
Definition

tiny hair-like or scale-like structures that grow from the outer surface of a plant, often helping to defend it against insects, reduce water loss, or shield it from strong sunlight

Example

The tiny trichomes on tomato stems give the plant a soft, fuzzy feel when touched.

collocation: trichomes on [plant part]

Some trichomes on nettle leaves contain chemicals that cause a sharp sting on bare skin.

Common collocations
  • glandular trichomes
  • leaf trichomes
  • stellate trichomes
  • trichomes secrete oils
Synonyms
  • plant hairs

    more informal and narrower; trichomes can also be scale-like or glandular, not just hair-shaped

  • setae

    used mainly in zoology for bristle-like structures on animals; trichomes is the botanical term

Usage Note

In botany, trichomes include many forms — simple hairs, branched stars, and gland-tipped stalks that produce oils or toxins. Distinguish from sense 2, which refers to cell chains in microorganisms, not plant structures.

Common Mistakes

The trichomes on the cat's tongue are rough.
The papillae on the cat's tongue are rough.
trichomes refer to plant or microbial structures, not animal tissue.

2. a thread-like chain of cells in certain bacteria and algae, where the cells stay

2.nounC2
Definition

a thread-like chain of cells in certain bacteria and algae, where the cells stay connected end to end after dividing, forming a visible strand under a microscope

Example

Dr. Okafor watched the trichomes of the cyanobacteria lengthen under the warm lab light.

collocation: trichomes of [organism]

In the pond water sample, long trichomes of green algae twisted slowly through the liquid.

Common collocations
  • bacterial trichomes
  • algal trichomes
  • cyanobacterial trichomes
  • trichomes elongate
Synonyms
  • filament

    broader term used across biology for any thread-like structure; trichomes specifies a chain of cells

  • cell chain

    more descriptive but less precise; trichomes is the standard technical term in microbiology

Usage Note

This sense is used in microbiology for filamentous colonies. Distinguish from sense 1 (PLANT HAIRS), which describes epidermal outgrowths on plants, not connected cell chains in microbes.

Common Mistakes

The trichomes on the rose leaf form long chains.
The trichomes on the rose leaf are hair-like outgrowths.
cell-chain trichomes (sense 2) belong to bacteria and algae, not plant leaves.

Word family

Synonym discussion

Sense: noun/1

Trichomes (sense 1) are often called 'plant hairs' in everyday language, but the technical term covers more than simple hairs — they can be star-shaped, scale-like, or topped with glands that produce oils and toxins. 'Bristles' are stiff and sharp, common on stems like those of borage; 'spines' are harder still and often modified leaves or stipules (like on a cactus), not epidermal outgrowths. 'Cilia' belong to the animal kingdom — they are tiny beating hairs on cells and microorganisms. The key difference: a trichome is always a plant's outer-layer structure, while bristles, spines, and cilia each belong to different biological contexts. Under a microscope, a tomato stem shows soft, simple trichomes; a nettle leaf shows stiff, hollow trichomes that sting; and a paramecium shows cilia that beat in rhythmic waves.

hairs ↗bristles ↗spines ↗cilia

Common collocations

Phrases

  • examine trichomes
  • dense covering of trichomes

Prepositions

  • trichomes on a leaf
  • trichomes under the microscope

Etymology

GreekScientific LatinEnglish

Borrowed in the 19th century from scientific Latin 'trichoma,' which came from the Greek word 'trikhōma' (τρίχωμα) meaning 'a growth of hair.' That word was built on 'thrix' (θρίξ), the Greek noun for 'hair.' Botanists first used the term for plant hairs, and microbiologists later applied it to thread-like bacterial colonies.

First known use

1875

1875, in the meaning defined above