from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The formation of a joint by the articulation of two bones
- n. An assimilation of the place of articulation of one speech sound to that of an adjacent speech sound.
from the GNU version of the Collaborative International Dictionary of English
- n. The union or articulation of bones to form a joint.
from The Century Dictionary and Cyclopedia
- n. Articulation one with another; especially, the articulation of the bones in a joint.
co- + articulation (Wiktionary)
At this point, in some IE dialects, the freely-variant aspiration seems to have become a required coarticulation with the plain-voiced stops.
Or perhaps pronounced with a coarticulation that is only possible if you have a Vietnamese uvula.