grat·is (grāt'ĭs, grä'tĭs, grā'-) adv.
& adj. Without charge.
[Middle English, from Latin grātīs, alteration of grātiīs, out of kindness, free, ablative pl. of grātia, kindness; see gwerə-2 in Indo-European roots.]
1444, "for nothing, freely," from L. gratis, contraction of gratiis "for thanks," hence, "without recompense," abl. of gratiæ "thanks," pl. of gratia "favor."