diminutive noun-forming element, Middle English, from Old French -elet, which often is a double-diminutive. It consists of Old French diminutive -et, -ette (see -et) added to nouns in -el, which in many cases represents Latin diminutive -ellus; see -el (2)). "The formation did not become common until the 18th c." [OED].
fem. word- and name-forming element, from Latin -ina (see -ine (1)), or its identical descendants in Spanish, Portuguese, or Italian. The French form is -ine. As a suffix in royal titles (czarina, etc.) it represents an extension from Latin regina.
standard ending in chemical names of sugars, originally simply a noun-forming suffix, taken up by French chemists mid-19c.; it has no etymological connection with sugar. It appears around the same time in two chemical names, cellulose, which would owe it to the French suffix, and glucose, where it would be a natural result from the Greek original. Flood favors origin from glucose.
word-forming element, Latin -plus "-fold." Watkins derives it from *-plo-, combining form of PIE root *pel- (2) "to fold" and makes it cognate with Old English -feald, Greek -paltos, -plos. But de Vaan connects it to PIE root *pele- (1) that yielded words meaning "much, many, more" and is the source of poly-.
before vowels ophthalm-, word-forming element meaning "eye," mostly in plural, "the eyes," from Greek ophthalmos "eye," originally "the seeing," a word of uncertain origin. Perhaps from ōps "eye" (from PIE root *okw- "to see") + a form related to thalamos "inner room, chamber" (see thalamus), giving the whole a sense of "eye and eye socket," but Beekes rejects all this and finds it to be probably Pre-Greek.
word-forming element technically meaning "something produced," but mainly, in modern use, "thing that produces or causes," from French -gène (18c.), from Greek -genes "born of, produced by," which is from the same source as genos "birth," genea "race, family," from PIE root *gene- "give birth, beget," with derivatives referring to procreation and familial and tribal groups. First used in late 18th century French chemistry (see oxygen), it probably involves a misunderstanding of -genes, as though it meant "that which produces."
word-forming element meaning "one who is immersed in or driven by," mostly from French-derived words, ultimately from Greek -logos, -logon (see -logy). Now mostly superseded by -loger, -logist except in ideologue and a few others. As a combining element meaning "kind of discourse," it is from French -logue, from Greek -logos.