aciculum

[uh-sik-yuh-luh m] /əˈsɪk yə ləm/
noun, plural aciculums, acicula
[uh-sik-yuh-luh] /əˈsɪk yə lə/ (Show IPA)
1.
an acicula.
2.
Zoology. one of the slender, sharp stylets embedded in the parapodia of certain annelid worms, as the polychaetes.
Origin
alteration of acicula
British Dictionary definitions for aciculum

aciculum

/əˈsɪkjʊləm/
noun (pl) -lums, -la (-lə)
1.
a needle-like bristle that provides internal support for the appendages (chaetae) of some polychaete worms
Word Origin
C19: New Latin; see acicula