spicula

noun

1. 1.A little spike; a spikelet.
2. 2.A pointed fleshy appendage.
3. 3.A thrusting javelin used by Romans that replaced the pilum in the late 3rd century.
4. 4.A sharp, pointed crystal, especially of ice.
5. 5.A sharp, needle-like structure, especially those making up the skeleton of a sponge.