What does annelid mean?
An annelid is any member of Annelida, a large phylum of segmented worms whose bodies are built from a chain of repeating ring-like segments. The group includes some of the most familiar animals on Earth — earthworms and leeches — as well as thousands of mostly marine polychaetes such as ragworms and tube worms. Annelids play vital ecological roles: earthworms aerate and enrich soil, while marine annelids are key players in ocean food webs and sediment turnover. The word derives from the Latin anellus, meaning 'little ring', reflecting the distinctive banded appearance of these animals. Because it is a precise scientific term, 'annelid' appears mainly in textbooks, field guides, and research writing rather than everyday speech, but it is indispensable for anyone describing worm biodiversity accurately.
nounA segmented worm of the phylum Annelida, which includes earthworms, leeches, and ragworms, characterized by a body divided into a series of ring-like segments.
- Any worm of the phylum Annelida, having a soft elongated body divided into repeated segments.
"The marine biologist identified the creature as a polychaete annelid rather than a flatworm."
"Earthworms are the most familiar annelids in temperate gardens."
"Leeches, though often feared, are blood-feeding annelids with remarkable medicinal uses."
Standard plural; used when referring to multiple individuals or members of the phylum collectively.
"Marine annelids display an astonishing diversity of feeding strategies."
Your body has roughly the same number of muscle segments as an earthworm's — both you and the worm are built on a repeating modular plan that biologists trace back to shared ancestry.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of annelid
The English word 'annelid' was borrowed from French 'annélide', coined by the French naturalist Jean-Baptiste Lamarck around the turn of the nineteenth century when he established the group as a class. It ultimately traces to the Latin 'anellus', a diminutive of 'anus' meaning 'ring' or 'little ring', chosen for the worm's segmented, ring-like body. Related English words from the same Latin root include 'annular', 'annulus', and 'annulate'.
How annelid is actually used
Primarily a technical term used in zoology, biology education, and natural-history writing; rare in casual conversation, where people simply say 'worm'. The plural 'annelids' is standard.
Easily confused with annelid
Nematodes are roundworms with unsegmented cylindrical bodies, whereas annelids are defined by their clearly segmented bodies.