Online Etymology Dictionary

-ia: word-forming element in names of countries, diseases, flowers, from Latin and Greek -ia, which forms abstract nouns of feminine gender. In paraphernalia, Mammalia, etc. it represents the Latin and Greek plural suffix of nouns in -ium or -ion.

Chinese forms country names by adding guo "country" to the stressed syllable of the place name, hence Meiguo "America," from mei, the stressed syllable of America (minus -r-, which does not exist in Chinese). Similarly Yingguo "England," Faguo "France." Continent names are similarly formed, with zhou "continent" (e.g. Meizhou "America (continent)," Feizhou "Africa," Ouzhou "Europe").
-ial: variant of -al (1).
-ian: variant of suffix -an used with stem endings in -i, from Latin -ianus (-anus). In Middle English, frequently -ien, from words borrowed via French.
-iana: form of -ana with nouns whose adjectival forms end in -ian.
-iasis: medical Latin word-forming element meaning "process; morbid condition," from Greek -iasis, from aorist of verbs in -iao, which often express disease.
-iatric: word-forming element from Greek iatrikos "healing," from iatros "physician, healer" (related to iatreun "treat medically," and iasthai "heal, treat"); of uncertain origin, perhaps from iaomai "to cure," related to iaino "heat, warm, cheer," probably from a root meaning "enliven, animate."
-iatry: word-forming element meaning "medical treatment," from French -iatrie, from Greek iatreia "healing, medical treatment" (see -iatric).
-ible: suffix forming adjectives from verbs, borrowed in Middle English from Old French -ible and directly from Latin -ibilis; see -able.
-ic: adjective suffix, "having to do with, having the nature of, being, made of, caused by, similar to" (in chemistry, indicating a higher valence than names in -ous), from French -ique and directly from Latin -icus, which in many cases represents Greek -ikos "in the manner of; pertaining to." From PIE *-(i)ko, which also yielded Slavic -isku, adjectival suffix indicating origin, the source of the -sky (Russian -skii) in many surnames.
-ical: adjectival suffix, mostly the same as -ic but sometimes with specialized sense (e.g. historic/historical), Middle English, from Late Latin -icalis, from Latin -icus + -alis.
-ics: in the names of sciences or disciplines (acoustics, aerobics, economics, etc.) it represents a 16c. revival of the classical custom of using the neuter plural of adjectives with -ikos (see -ic) to mean "matters relevant to" and also as the titles of treatises about them. Subject matters that acquired their names in English before c.1500, however, tend to remain in singular (e.g. arithmetic, logic).
-id: word-forming element meaning "belonging to, connected with, member of a group or class" (plural -idae), from French -ide and directly from Latin -ides, masculine patronymic, from Greek -ides. In astronomy, of meteor showers, it represents Latin -idis, Greek -idos, the genitive of the feminine patronymic suffix.
-idae: word-forming element used to form family names in zoology, Latin plural noun suffix, plural of -ides (see -id).
-ide: suffix used to form names of simple compounds of an element with another element or radical; originally abstracted from oxide, the first so classified.
-ie: alternative spelling of -y; now mostly of -y (3), but formerly of others.
-ier: word-forming element indicating occupation, from French and Old French -ier, from Latin -arius (also see -er (1)). Nativized and used to form English words (glazier, hosier, etc.; also see -yer).
-ify: variant of suffix -fy used with stem endings in -i.
-ile: suffix denoting ability, capacity, from French -il or directly from Latin -ilis.
-in (1): suffix attached to a verb, first attested 1960 with sit-in (which probably was influenced by sit-down strike); used first of protests, extended c.1965 to any gathering.
-in (2): chemical suffix, usually indicating a neutral substance, antibiotic, vitamin, or hormone; see -ine (2).
-ina: fem. suffix in titles and names, from Latin -ina.
-ine (1): suffix used to form adjectives from nouns, from French -ine, fem. of -in, or directly from Latin -inus "of, like."
-ine (2): chemical suffix, sometimes -in, though modern use distinguishes them; early 19c., from French -ine, from Latin -ina, fem. form of suffix used to form adjectives from nouns. In French commonly used to form words for derived substances, hence its extended use in chemistry.
-ing (1): suffix attached to verbs to mean their action, result, product, material, etc., from Old English -ing, -ung, from Proto-Germanic *unga (cf. Old Norse -ing, Dutch -ing, German -ung). Originally used to form nouns from verbs and to denote completed or habitual action. Its use has been greatly expanded in Middle and Modern English.
-ing (2): suffix used form the present participle of verbs, from Old English -ende (cf. German -end, Gothic -and, Sanskrit -ant, Greek -on, Latin -ans). It evolved into -ing in 13c.-14c.
-ion: suffix forming nouns of state, condition, or action from verbs, from Latin -ionem (nominative -io), sometimes via French -ion.
-ise: see -ize.
-ish: adjectival suffix, from Old English -isc, common Germanic (cf. Old Norse -iskr, German -isch, Gothic -isks), cognate with Greek diminutive suffix -iskos. Colloquially attached to hours to denote approximation, 1916.
-ism: suffix forming nouns of action, state, condition, doctrine, from French -isme or directly from Latin -isma, -ismus, from Greek -isma, from stem of verbs in -izein. Used as an independent word, chiefly disparagingly, from 1670s.
-ist: agent noun suffix, also used to indicate adherence to a certain doctrine or custom, from French -iste and directly from Latin -ista, from Greek -istes, from agential suffix -tes. Variant -ister (e.g. chorister, barister) is from Old French -istre, on false analogy of ministre. Variant -ista is from Spanish form, popularized in English 1970s by names of Latin-American revolutionary movements.
-istic: adjectival suffix, from Latin -isticus (often via French -istique), from Greek -istikos, which is adjective suffix -ikos (see -ic) added to noun suffix -istes (see -ist).
-ite (1): 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.
-ite (2): salt suffix, from French -ite, alteration of -ate (see -ate (3)).
-itis: noun suffix denoting diseases characterized by inflammation, Modern Latin, from Greek -itis, feminine of adjectival suffix -ites "pertaining to." Feminine because it was used with feminine noun nosos "disease," especially in Greek arthritis (nosos) "(disease) of the joints," which was one of the earliest borrowings into English and from which the suffix was abstracted in other uses.
-ity: suffix forming abstract nouns from adjectives, meaning "condition or quality of being ______," from Middle English -ite, from Old French -ité and directly from Latin -itatem (nominative -itas), suffix denoting state or condition, composed of connective -i- + -tas (see -ty (2)).
Roughly, the word in -ity usually means the quality of being what the adjective describes, or concretely an instance of the quality, or collectively all the instances; & the word in -ism means the disposition, or collectively all those who feel it. [Fowler]
-ive: sufix forming adjectives from verbs, meaning "pertaining to, tending to," in some cases from Old French -if, but usually directly from Latin -ivus. In some words borrowed from French at an early date it has been reduced to -y (e.g. hasty, tardy).
-ization: suffix forming nouns of action, process, or state; see -ize + -ation.
-ize: word-forming element used to make verbs, Middle English -isen, from Old French -iser, from Late Latin -izare, from Greek -izein.

English picked up the French form, but partially reverted to the correct Greek -z- spelling from late 16c. In Britain, despite the opposition (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- (e.g. advertise, devise, surprise).
I (pron.): 12c. shortening of Old English ic, first person singular nominative pronoun, from Proto-Germanic *ekan (cf. Old Frisian ik, Old Norse ek, Norwegian eg, Danish jeg, Old High German ih, German ich, Gothic ik), from PIE *eg-, nominative form of the first person singular pronoun (cf. Sanskrit aham, Hittite uk, Latin ego (source of French Je), Greek ego, Russian ja, Lithuanian aš). Reduced to i by mid-12c. in northern England, it began to be capitalized mid-13c. to mark it as a distinct word and avoid misreading in handwritten manuscripts.
The reason for writing I is ... the orthographic habit in the middle ages of using a 'long i' (that is, j or I) whenever the letter was isolated or formed the last letter of a group; the numeral 'one' was written j or I (and three iij, etc.), just as much as the pronoun. [Otto Jespersen, "Growth and Structure of the English Language," p.233]
The form ich or ik, especially before vowels, lingered in northern England until c.1400 and survived in southern dialects until 18c. The dot on the "small" letter -i- began to appear in 11c. Latin manuscripts, to distinguish the letter from the stroke of another letter (such as -m- or -n-). Originally a diacritic, it was reduced to a dot with the introduction of Roman type fonts.
I Ching: 1876, from Chinese, said to mean "Book of Changes."
i'nt: also i'n't, 18c., contraction representing a casual pronunciation of isn't it.
I'se: colloquial or dialectal contraction of I shall, attested from 1796.
I've: contraction of I have, 1742, first attested in Richardson's "Pamela."
I.D.: also ID (but pronounced as separate letters), short for identification, attested from 1955.
i.e.: abbreviation of Latin id est, literally "that is;" used in English in the sense of "that is to say."
I.H.S.: Old English, from Medieval Latin, representing Greek abbreviation of IHSOUS "Jesus," in which -H- is the capital of the Greek vowel eta. The Roman form would be I.E.S. Mistaken for a Latin contraction in the Middle Ages, after its Greek origin was forgotten, and sometimes treated as short for Iesus Hominum Salvator "Jesus Savior of Men." Alternative version I.H.C. (terminal -s- often written in later Greek with a character resembling -c-) is found on vestments from 950 C.E., and may be the source of the H. in slang Jesus H. Christ.
I.O.U.: also IOU, I O U, 1610s, originally as IOV (see V); with punning reference to "I Owe You."
I.Q.: 1922, abbreviation of intelligence quotient, a 1921 translation of German Intelligenz-quotient, coined 1912 by German psychologist William L. Stern (1871-1938).
Intelligence is a general capacity of an individual consciously to adjust his thinking to new requirements: it is general mental adaptability to new problems and conditions of life. [Stern, "The Psychological Methods of Testing Intelligence," 1914]
I.R.A. (2): also IRA, initialism for individual retirement account, attested from 1974.
I.R.A. (1): also IRA, initialism for Irish Republican Army, attested from 1919.