What's the "een" in Halloween?
"forked," 1819, from Medieval Latin furcatus, from Latin furca (see fork). As a verb, from 1828 (implied in furcated).
furcation fur·ca·tion (fûr-kā'shən)n.
A forking, or a forklike part or branch.
The region of a multirooted tooth at which the root divides.