Pronunciation: (spik'yOOl),[key] —n. 1. a small or minute, slender, sharp-pointed body or part; a small, needlelike crystal, process, or the like.
2. Zool.one of the small, hard, calcareous or siliceous bodies that serve as the skeletal elements of various marine and freshwater invertebrates.
3. Astron.a jet of gas several hundred miles in diameter rising from the sun's surface to heights of 3000 to 6000 miles (4800 to 9600 km).