spicule Definition

spicule
noun

1. Something that is small, sharp, hard and pointed, such as a splinter, a shard of glass, crystal or bone, etc.
2. zool.
A sharp pointed process, such as any of the needle-like projections that form the firm part of a sponge.
3. bot.
A small flower spike.
4. astron.
A spiked projection that can be seen in the corona of the Sun and which is caused by shooting jets of gas in the Sun's atmosphere.

Etymology: 18c: French, from Latin spiculum a sharp point.