What does spicule mean?
A spicule is a tiny, pointed, usually rigid structure. Its best-known use is in biology: many sponges contain microscopic needle-like spicules made of silica or calcium carbonate, arranged to support and protect the animal’s body. Similar structures occur in other organisms and in some mineral formations, where they may be referred to as small spines or pointed projections. The term is more technical and precise than “spike,” and it generally suggests a structure that is both small and sharply tapered. Spicules can be diagnostic in scientific descriptions, helping researchers identify organisms and understand their anatomy or composition. Although the word is relatively uncommon in everyday speech, it is useful when discussing the structural elements of sponges, radiolarians, plants, and minerals.
A small, slender, pointed structure, especially a hard, needle-like element forming part of the supporting framework of a sponge or other organism.
"The animal is supported by a framework of tiny mineral spicules."
In zoological and anatomical contexts, the word commonly denotes a microscopic or very small pointed skeletal element.
A small pointed projection or spine occurring on a plant, mineral, or other biological structure.
"The leaf surface bears numerous sharp spicules."
This broader sense is less common than the biological use but occurs in specialized descriptions.
The plural is spicules, pronounced with a final unstressed syllable.
"The sponge has numerous spicules embedded in its body wall."
In many sponges, the tiny spicules woven together form a microscopic skeleton that supports the animal's body.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does spicule come from?
The word comes through Latin spicula, a diminutive of spicum, meaning “spike” or “point.” English borrowed the term in the sense of a small pointed structure, especially in descriptions of the hard elements of sponges. The same Latin root underlies related words such as spike, spiky, and spiny.
Related word forms
How spicule is actually used
The word is chiefly used in technical biology, paleontology, and mineralogy. It is more specific than the general word “spike,” and its use often implies a small, rigid, pointed structure.
Easily confused with spicule
A spicule is a small pointed projection, whereas a spindle is an elongated, tapering rod or tool, and it may also refer to a type of sleep or lying position.