specialisation (n.)

1831, "act of becoming specialized," noun of action from specialize. Biological sense from 1862. In science and scientific education, "a direction of time and energies in one particular channel to the exclusion of others," by 1880.

If you peruse the people in the news

The people that the magazines refer to

You'll find that they are naturally soignée

The special ones that all of us defer to

They've each a trait that seems to state first raters

That separates them from the small potaters

["Specialization," lyrics by Sammy Cahn]

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.