- gratis (adv.)
[gratis 词源字典]
- mid-15c., "for nothing, freely," from Latin gratis, contraction of gratiis "for thanks," hence, "without recompense, for nothing," ablative of gratiae "thanks," plural of gratia "favor" (see grace (n.)). Meaning "free of charge" is 1540s.[gratis etymology, gratis origin, 英语词源]