c. 1400, negatif, "expressing denial" (a sense now rare or obsolete), from Anglo-French negatif (early 14c.), Old French negatif (13c.) and directly from Latin negativus "that which denies," from negat-, past-participle stem of negare "deny, say no" (see deny).
The meaning "expressing negation" is from c. 1500; that of "characterized by absence of that which is affirmative or positive" is from 1560s. Algebraic sense, denoting quantities which are a subtraction from zero, is from 1670s. The electricity sense is from 1755.
Negative Capability, that is when a man is capable of being in uncertainties, Mysteries, doubts without any irritable reaching after fact and reason. [John Keats, letter, Dec. 21, 1817]
late 14c., "a prohibition" (a sense now obsolete), also "absence, nonexistence; opposite," from Old French negatif and directly from Latin negativus (see negative (adj.)).
Meaning "a negative statement" is from 1560s. Sense of "that side of a question which denies what the opposite side affirms" is from 1570s. Meaning "the right or power of refusing assent" is from 1610s. Meaning "a negative quality" is from 1640s. In mathematics, "a negative number," from 1706. Photographic sense of "image in which the lights and shades are the opposite of those in nature" is recorded by 1853. As a response, "I refuse, disagree, no," from 1945, originally in radio communication.