Etymology
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amp (n.)
1886 as an abbreviation of ampere; 1967 as an abbreviation of amplifier.
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amplifier (n.)
1540s; agent noun from amplify. Electronic sense is from 1914; shortened form amp is from 1967. Alternative stentorphone (1921) did not catch on.
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ampere (n.)
1881, "the current that one volt can send through a resistance of one ohm," from French ampère, named for French physicist André-Marie Ampère (1775-1836). Adopted by the Electric Congress at Paris in 1881. Shortened form amp is attested from 1886.
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preamplifier (n.)

"a device designed to amplify a weak source and pass it to another amplifier," 1929, from pre- + amplifier. Shortened form pre-amp is attested by 1957.

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amphetamine (n.)
"synthetic heart-stimulating drug," 1938, contracted from alphamethyl-phenethylamine.
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amphibian (adj.)

1630s, "having two modes of existence; of doubtful nature," from Greek amphibia, neuter plural of amphibios "living a double life," from amphi "of both kinds" (see amphi-) + bios "life," from PIE root *gwei- "to live."

Formerly used by zoologists to describe any sort of animal at home on land and in the water, including crocodiles, walruses, beavers, seals, hippopotami; the restriction to the class of animals between fishes and reptiles with life cycles that begin in water and mature on land is from 1835; Amphibia has been used a zoological classification in this sense since 1788.

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ample (adj.)
mid-15c., "great, abundant," especially "sufficient for any purpose," from Old French ample "large, wide, vast, great" (12c.), from Latin amplus "large, spacious; abundant, numerous; magnificent, distinguished," which is related to ampla "handle, grip; opportunity," from Proto-Italic *amlo- "seizable," from a PIE root meaning "to grab" that also is postulated as the source of amare "to love" (see Amy).
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amputation (n.)

1610s, "a cutting off of tree branches, a pruning," also "operation of cutting off a limb, etc., of a body," from French amputation or directly from Latin amputationem (nominative amputatio), noun of action from past-participle stem of amputare "to cut off, lop off; cut around, to prune," from am(bi)- "around" (from PIE root *ambhi- "around") + putare "to prune, trim" (from PIE root *pau- (2) "to cut, strike, stamp").

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amphibious (adj.)
1640s, "combining two qualities; having two modes of life," especially "living both on land and in water," from Latinized form of Greek amphibios "having a double life; living on land and in water" (see amphibian (adj.)). Of motor vehicles, from 1915.
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amputee (n.)
1910, perhaps on a French model; see amputation + -ee.
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