imitative of laughter, Old English.
Ha ha and he he getacniað hlehter on leden and on englisc. [Ælfric, "Grammar," c. 1000]
"pertaining to or affected by a mode," 1560s, originally a term in logic, from French modal and directly from Medieval Latin modalis "of or pertaining to a mode," from Latin modus "measure, extent, quantity; proper measure, rhythm, song; a way, manner, fashion, style" (in Late Latin also "mood" in grammar and logic), from PIE root *med- "take appropriate measures." Musical sense is from 1590s; In grammar from 1798.
1520s, originally in grammar, from positive (adj.). Sense of "that which can be affirmed, reality" is from 1610s. Sense in photography (opposite of negative (n.)) is by 1853.
late 15c., from French formatif, from Latin format-, past-participle stem of formare "to form," from forma "form, shape" (see form (n.)). As a noun, in grammar, from 1816.
"indication, pointing out," 1949, in grammar, from Greek deixis "reference," from deiknynai "to show" (from PIE root *deik- "to show"). Related: Deictic.
late 14c., privatif, "characterized by absence of a quality, characterized by taking away or removal of something," from Latin privativus "denoting privation," in grammar, "negative," from privatus, past participle of privare "to deprive, rob, strip" of anything; "to deliver from" anything" (see private (adj.)).