What is the meaning of Articulus?

A joint of the cirri of the Crinoidea.

A joint or segment of an arthropod appendage.

a point connecting various parts of the body; joint, knot, knuckle.

a limb, member, finger

a short clause; a single word; pronoun, pronominal adjective or article

a member, part, division, point, article

a point in time, moment; division of time, space

a positive decimal integer consisting of a non-zero digit multiplied by a positive integral power of ten.

Source: wiktionary.org