因由 is read as いんゆ (inyu) and means cause.
いんゆ
inyu
げんいんにおいてじゆうなこうい
actio libera in causa
いん
hetu (direct cause, esp. as opposed to indirect conditions)
いんし
factor
いんが
cause and effect
いんしゅう
convention
ちなみに
by the way
いんすうていり
factor theorem
いんししゅうごう
factor set
いんすうぶんかい
factorization
いんがかんけい
relation of cause and effect
よるところがおおきい
depending largely on
いんがせい
causality