1. A technical name for a slender needle-like body; such as, the spines or prickles with which some animals and plants are furnished, or the needle-like crystals of certain minerals.
2. A needle-shaped part, as of a plant or crystal.

1. A needle-like spine or bristle, as is present in certain types of worms or flagellates.
2. A projecting cluster of bristles or setae found in certain annelid worms or a fingerlike or handlike bristle seen in certain flagellate protozoa.
3. In zoology, one of the slender, sharp stylets embedded in the parapodia of certain annelid worms, as the polychaetes.
4. A technical name for a slender needle-like body; such as, the spines or prickles with which some animals and plants are furnished, or the needle-like crystals of certain minerals.