amalgamize v.

c. 1400, "a blend of mercury with another metal; soft mass formed by chemical manipulation," from Old French amalgame or directly from Medieval Latin amalgama, "alloy of mercury (especially with gold or silver)," c. 1300, an alchemists' word, probably from Arabic al-malgham "an emollient poultice or unguent for sores (especially warm)" [Francis Johnson, "A Dictionary of Persian, Arabic, and English"], which is itself perhaps from Greek malagma "softening substance," from malassein "to soften," from malakos "soft" (from PIE *meldh-, from root *mel- (1) "soft"). The figurative meaning "compound of different things" is from 1790.

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.

1650s, "mix (a metal) with mercury," a back-formation from amalgamation, or else from the obsolete adjective amalgamate (1640s) from amalgam (q.v.). Originally in metallurgy. The figurative transitive sense of "to unite" (races, etc.) is attested from 1802; the intransitive sense of "to combine, unite into one body" is from 1797. Related: Amalgamated; amalgamating. Earlier verbs were amalgam (1540s); amalgamize (1590s).