early 15c., "brief, abbreviated; containing the sum or substance only," from Medieval Latin summarius "of or pertaining to the sum or substance," from Latin summa "whole, totality, gist" (see sum, n.). Compare Latin phrase ad summam "on the whole, generally, in short." Sense of "done promptly, performed without hesitation or formality" is from 1713.

"a summary statement or account," c.1500, from Latin summarium "an epitome, abstract, summary," from summa "totality, gist" (see sum, n.).