1. small, needle-like structures or projections, especially those found in sponges, sea urchins, and other marine organisms
Usage: biology; zoology
2. thin jets of gas that shoot upward from the sun’s surface
Usage: astronomy

Examples

• The sponge’s spicules provide structural support and protection.
• Marine biologists examined the calcium carbonate spicules under a microscope.
• Sea urchin spicules are made of calcite crystals.
• Solar spicules can reach heights of several thousand kilometers.
• The telescope captured images of spicules erupting from the sun’s chromosphere.
• Researchers studied how spicules form in different species of sponges.