1. To unite (blood vessels, nerve fibers, or ducts) by small openings
2. To make continuous; blend
1. To open into one another
2. To unite so as to be continuous; blend.
I came across this word as the noun 'inosculation'. Inosculation most often refers to the phenomenon of two trees becoming joined at the trunks, branches, or roots.
It can happen naturally, or can be done intentionally.
One of the cooler examples of inosculation is as a tool for building living root bridges (other methods are used as well).
The pic below is from the Wikipedia article on inosculation.
Etymology: Latin osculare, to provide with an opening.