In Molluscs the sack-shaped and non-articulate body is the distinguishing feature.
It is a striking fact that certain of these non-articulate “lamp-shells” are familiar inhabitants of our present seas.
1590s, "to divide speech into distinct parts" (earlier "to formally bring charges against," 1550s), from Latin articulatus, past participle of articulare "to separate into joints," also "to utter distinctly," from articulus "joint" (see article). Generalized sense of "express in words" is from 1690s. Literal sense, "to join, to attach by joints," is attested from 1610s. Earlier senses, "to set forth in articles," "to bring a charge against" (1560s) now are obsolete or nearly so. Related: Articulated; articulating.
1580s in the speech sense (1570s as "formulated in articles"), from Latin articulatus (see articulate (v.)). Literal meaning "composed of segments united by joints" is from c.1600; the general sense of "speaking accurately" is short for articulate-speaking (1829). Related: Articulately.
articulate ar·tic·u·late (är-tĭk'yə-lĭt)
Capable of speaking distinctly and connectedly.
Consisting of sections united by joints; jointed.
To speak distinctly and connectedly.
To join or connect together loosely to allow motion between the parts.
To unite by forming a joint or joints.
To form a joint; be jointed.