Entries linking to routinization
"customary course of action; more or less mechanical performance of certain acts or duties," 1670s, from French routine "usual course of action, beaten path" (16c.), from route "way, path, course" (see route (n.)) + noun suffix -ine (see -ine (1)). The theatrical or athletic performance sense of "carefully rehearsed sequence of actions" is by 1926. The adjective, "of a mechanical or unvaried character, habitually done in the same way" is attested by 1817, from the noun. Related: Routinely.
word-forming element used to make verbs, Middle English -isen, from Old French -iser/-izer, from Late Latin -izare, from Greek -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached.
The variation of -ize and -ise began in Old French and Middle English, perhaps aided by a few words (such as surprise, see below) where the ending is French or Latin, not Greek. With the classical revival, English partially reverted to the correct Greek -z- spelling from late 16c. But the 1694 edition of the authoritative French Academy dictionary standardized the spellings as -s-, which influenced English.
In Britain, despite the opposition to it (at least formerly) of OED, Encyclopaedia Britannica, the Times of London, and Fowler, -ise remains dominant. Fowler thinks this is to avoid the difficulty of remembering the short list of common words not from Greek which must be spelled with an -s- (such as advertise, devise, surprise). American English has always favored -ize. The spelling variation involves about 200 English verbs.