The Cambridge Guide to Australian English Usage - Noel's ESL ...

its or it’s
In common usage -ite normally attaches itself to proper names. Cases such as
socialite and suburbanite are the exception. Much more often it picks up a place
name, as in Brooklynite, Canaanite or Muscovite; or that of a notable person, as in
Ibsenite, Thatcherite or Trotskyite; or that of a party or movement, as in Laborite
and pre-Raphaelite. The suffix sometimes seems derogatory, though not all the
examples given would show this. At any rate, the -ite word tends to be used by
those opposed to the person or party named, while supporters and adherents are
unlikely to apply it to themselves. Darwinite is probably less neutral than Darwinist
or Darwinian. (See further under -an and -ist.)
In scientific usage, -ite again has more than one function. In geology it serves
as a regular suffix for naming minerals, such as anthracite, dolomite and malachite;
and for the names of various fossils: ammonite, lignite and trilobite. In chemistry
it’s used for naming both explosives such as dynamite and melinite, as well as the
salts of certain acids (those whose names end in -ous), for example nitrite and sulfite.
The fictional name kryptonite (the only substance that can reduce Superman to a
trembling heap) seems to carry the aura of several of these scientific uses.
Itie, eyetie or eytie None of these makes good contact with the intended
reference: an Italian. The first spelling has trouble representing the sound of the
second syllable; the second and third spellings mask the fact that it is a proper name.
Yet we need feel no regrets if the word misses its target. Its overtones
are derogatory, and it’s most often heard in utterances that express ethnic
discrimination. Better by far to replace it with the neutral word Italian, with its
straightforward geographical and historical associations.
See further under inclusive language and racist language.
-itis This is essentially a medical suffix, creating nouns which mean “inflammation
of . . .”, as in:
appendicitis bronchitis gastroenteritis mastitis tonsillitis
It also enjoys some popular use in coining words which refer to pseudo-diseases,
such as Mondayitis.
its or it’s Separated only by an apostrophe, there are few pairs in English which
cause as much trouble as this. The problem is mostly that it’s is written instead of
its—which is to say that it’s is most probably the one you need, other things being
equal.
Its without the apostrophe is a possessive pronoun or adjective, pure and simple.
Like other pronouns: his, her(s), our(s) etc, it has no apostrophe. What confuses the
issue is the fact that nouns do have apostrophes when they are possessive, as in the
dog’s breakfast or a baker’s dozen. Inexperienced writers therefore think that it’s
is the possessive they need, especially if they have been rapped over the knuckles
for leaving apostrophes out.
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