early 15c., "effective as a cause or agent," from Old French causatif, from Latin causativus, from causa "a cause, reason" (see cause (n.)). Meaning "expressing causation" is from c. 1600; hence the noun, in grammar, "a form of a noun or verb expressing causation" (1824).
1590s (implied in proximately), "closely neighboring; next, immediate, without intervention of a third," from Late Latin proximatus, past participle of proximare "to draw near, approach," from proximus "nearest, next; most direct; adjoining," figuratively "latest, most recent; next, following; most faithful," superlative of prope "near" (see propinquity). Meaning "coming next in a chain of causation" is by 1660s. Related: Proximately.
1846, introduced by William Hamilton for "doctrine of the necessitarian philosophers" (who hold that human action is not free but necessarily determined by motives, regarded as external forces acting on the will or character of the person). See determine + -ism.
Determinism does not imply materialism, atheism, or a denial of moral responsibility; while it is in direct opposition to fatalism and to the doctrine of the freedom of the will. [Century Dictionary]
From 1876 in general sense of "doctrine that everything happens is determined by a necessary chain of causation," from French déterminisme, from German Determinismus, perhaps a back-formation from Praedeterminismus.
"an act of explaining; a meaning or interpretation assigned," late 14c., explanacioun, from Latin explanationem (nominative explanatio) "an explanation, interpretation," noun of action from past-participle stem of explanare "to make plain or clear, explain," literally "make level, flatten," from ex "out" (see ex-) + planus "flat" (from PIE root *pele- (2) "flat; to spread").
An individual fact is said to be explained, by pointing out its cause, that is, by stating the law or laws of causation of which its production is an instance. Thus. a conflagration is explained, when it is proved to have arisen from a spark falling into the midst of a heap of combustibles. [J.S. Mill, "Logic"]