abbreviation of Before Christ, in chronology, attested by 1823. The phrase itself, Before Christ, in dating, with exact years, is in use by 1660s.
c. 1600, "emptiness, hollowness," literal and figurative, from French inanité (14c.) or directly from Latin inanitas "emptiness, empty space," figuratively "worthlessness," noun of quality from inanis "empty, void; worthless, useless," a word of uncertain origin. De Vaan writes that "The chronology of attestations suggests that 'empty, devoid of' is older than 'hollow'." Meaning "silliness, want of intelligence" is from 1753.
early 15c., scocchen "to cut, score, gash, make an incision," a word of obscure origin. Century Dictionary considers that it might be a deformation of scratch. Chronology rules out connection with scorch. Perhaps [Barnhart] from Anglo-French escocher, Old French cocher "to notch, nick," from coche "a notch, groove," perhaps from Latin coccum "berry of the scarlet oak," which appears notched, from Greek kokkos.
The meaning "stamp out, crush" (often figurative, of abstract things) is by 1825, earlier "make harmless for a time, wound slightly" (1798), a sense that derives from an uncertain reading of "Macbeth" III.ii.13). Related: Scotched; scotching.
c. 1300, cronicle, "historical account of facts or events in the order of time," from Anglo-French cronicle, from Old French cronique "chronicle" (Modern French chronique), from Latin chronica (neuter plural mistaken for fem. singular), from Greek ta khronika (biblia) "the (books of) annals, chronology," neuter plural of khronikos "of time, concerning time," from khronos "time" (see chrono-).
The ending was modified in Anglo-French, perhaps by influence of article. Old English had cranic "chronicle," cranicwritere "chronicler." The classical -h- was restored in English from 16c. As a one-word form, classical Greek had khronographia "chronicle, yearbook."