"the branch of dentistry concerned with the treatment of irregularities of the teeth and jaws," 1849, from ortho- "straight, regular" + Greek odon (genitive odontos) "tooth" (from PIE root *dent- "tooth") + abstract noun ending -ia.

"inflammation beside a fingernail," 1590s, from Latin, from Greek paronykhia "whitlow," from para- "beside" (see para- (1)) + onyx "nail" (see nail (n.)) + abstract noun ending -ia.

"inflammation of the eye, conjunctivitis," late 14c., obtalmia, from Medieval Latin obtalmia and Old French obtalmie, ultimately from Greek ophthalmia, from ophthalmos (see ophthalmo-) + -ia. The corrected spelling is attested from late 16c.

"the East Indies," 1850, from Indo- "India" + Greek nēsos "island" (see Chersonese) + -ia. Formerly called Indian Archipelago or East Indies Islands (see Indies). Related: Indonesian "of or from the East Indies" (1850).

fatal genetic disease of children causing rapid aging, 1902, Modern Latin, from Greek progeros "prematurely old;" from pro "before, sooner" (see pro-) + geras "old man" (see geriatric) + abstract noun ending -ia.

"adolescent insanity," 1886, coined in Modern Latin by German psychiatrist Ewald Escker in 1871, from Greek hēbē "youth" (see Hebe (1)) + phrene "mind" (see phreno-) + abstract noun ending -ia. Related: Hebephreniac.

"inability to feel pleasure," 1897, from French anhédonie, coined 1896 by French psychologist Theodule Ribot as an opposite to analgesia, from Greek an- "not, without" (see an- (1)) + hedone "pleasure" (see hedonist) + abstract noun ending -ia.