Meaning

noun the primary form of an adjective or adverb; denotes a quality without qualification, comparison, or relation to increase or diminution

noun a film showing a photographic image whose tones correspond to those of the original subject

adjective characterized by or displaying affirmation or acceptance or certainty etc.

originFrom Old French positif, from Latin positivus, from the past participle stem of ponere (“to place”). Compare posit.

Etymology from Wiktionary, CC BY-SA 3.0