-ite1

1.
a suffix of nouns denoting especially persons associated with a place, tribe, leader, doctrine, system, etc. (Campbellite; Israelite; laborite); minerals and fossils (ammonite; anthracite); explosives (cordite; dynamite); chemical compounds, especially salts of acids whose names end in -ous (phosphite; sulfite); pharmaceutical and commercial products (vulcanite); a member or component of a part of the body (somite).
Compare -itis.
Origin
Middle English < Latin -ita < Greek -itēs; often directly < Greek; in some words representing French -ite, German -it, etc. < Latin < Greek, as above

-ite2

1.
a suffix forming adjectives and nouns from adjectives, and from some verbs:
composite; opposite; erudite; requisite.
Origin
< Latin -itus or -ītus past participle suffix
British Dictionary definitions for -ite

-ite1

suffix
1.
a native or inhabitant of: Israelite
2.
a follower or advocate of; a member or supporter of a group: Luddite, labourite
3.
(in biology) indicating a division of a body or organ: somite
4.
indicating a mineral or rock: nephrite, peridotite
5.
indicating a commercial product: vulcanite
Word Origin
via Latin -ita from Greek -itēs or directly from Greek

-ite2

suffix
1.
indicating a salt or ester of an acid having a name ending in -ous: a nitrite is a salt of nitrous acid
Word Origin
from French, arbitrary alteration of -ate1
Word Origin and History for -ite

from French -ite and directly from Latin -ita, from Greek -ites (fem. -itis), forming adjectives and nouns meaning "connected with or belonging to." Especially used in classical times to form ethnic and local designations (e.g. use in Septuagint for Hebrew names in -i) and for names of gems and minerals.

salt suffix, from French -ite, alteration of -ate (see -ate (3)).

-ite in Medicine

-ite 1
suff.

  1. A part of an organ, body, or bodily part: somite.

  2. Product: metabolite.

-ite 2
suff.
A salt or ester of an acid named with an adjective ending in -ous: sulfite.

-ite in Science
-ite  

  1. A suffix used to form the names of minerals, such as hematite and malachite.

  2. A suffix used to form the name of a salt or ester of a specified acid whose name ends in -ous. Such salts or esters have one oxygen atom fewer than corresponding salts or esters with names ending in -ate. For example, a nitrite is a salt of nitrous acid and contains the group NO2, while a nitrate contains NO3. Compare -ate.