In Aristotle's theory of the four causes, the efficient cause refers to the immediate trigger that sets things in motion.
彫刻における作用因は彫刻家である。
The efficient cause of a sculpture is the sculptor.
Formal cause: the form, pattern, or essence that defines what a thing is.
Final cause: the purpose or end for which something is done.
Compound of 作用 (action, effect) and 因 (cause), used as a technical translation of Aristotle's efficient cause.