affinity (n.)

word-forming element expressing direction toward or in addition to, from Latin ad "to, toward" in space or time; "with regard to, in relation to," as a prefix, sometimes merely emphatic, from PIE root *ad- "to, near, at."

Simplified to a- before sc-, sp- and st-; modified to ac- before many consonants and then re-spelled af-, ag-, al-, etc., in conformity with the following consonant (as in affection, aggression). Also compare ap- (1).

In Old French, reduced to a- in all cases (an evolution already underway in Merovingian Latin), but French refashioned its written forms on the Latin model in 14c., and English did likewise 15c. in words it had picked up from Old French. In many cases pronunciation followed the shift.

Over-correction at the end of the Middle Ages in French and then English "restored" the -d- or a doubled consonant to some words that never had it (accursed, afford). The process went further in England than in France (where the vernacular sometimes resisted the pedantic), resulting in English adjourn, advance, address, advertisement (Modern French ajourner, avancer, adresser, avertissement). In modern word-formation sometimes ad- and ab- are regarded as opposites, but this was not in classical Latin.

late 14c., "to bring to an end;" mid-15c., "to come to an end" (intransitive), from Old French finiss-, present participle stem of fenir "stop, finish, come to an end; die" (13c.), from Latin finire "to limit, set bounds; put an end to; come to an end," from finis "that which divides, a boundary, border," figuratively "a limit, an end, close, conclusion; an extremity, highest point; greatest degree," which is of unknown origin, perhaps related to figere "to fasten, fix" (see fix (v.)). Meaning "to kill, terminate the existence of" is from 1755.

colorless, tasteless fatty crystalline substance obtained from petroleum, etc., 1838, from German Paraffin, coined c. 1830 by German chemist Karl von Reichenbach (1788-1869), who first obtained it as a waxy substance from wood tar, irregularly from Latin parum "not very, too little," which probably is related to parvus "little, small" (from PIE root *pau- (1) "few, little") + affinis "associated with" (see affinity). So called because paraffin is chemically not closely related to other substances. The liquid form (originally paraffin oil) Reichenbach called eupion, but this was the standard meaning of paraffin in English by 1860.