分木 is read as ぶんぎ (bungi) and means -ary tree.
ぶんぎ
bungi
にぶんぎ
binary tree
ぶぶんもく
subtree
にぶんたんさくぎ
binary search tree
かいぶぶんもく
subordinate subtree
わかる
I know!
ぶんや
field
わける
to push one's way through (a crowd)
ぶんし
molecule
わかれる
to disperse
ぶんぎょう
division of labor
ぶんりつ
segregation
ぶんべつ
separation (e.g. of rubbish when recycling)