1610s, "the point at which something splits in two," noun of action from bifurcate (v.). Meaning "division into two forks" is from 1640s.
bifurcation bi·fur·ca·tion (bī'fər-kā'shən)
A division into two branches; a forking.
bifurcate bi·fur·cate (bī'fər-kāt', bī-fûr'-)
v. bi·fur·cat·ed, bi·fur·cat·ing, bi·fur·cates
To divide into two parts or branches. adj. (-kāt', -kĭt)
Forked or divided into two parts or branches.