Origin of alternate

First recorded in 1505–15, alternate is from the Latin word alternātus (past participle of alternāre). See altern, -ate1
Related formsal·ter·nate·ly, adverbal·ter·nate·ness, nounal·ter·nat·ing·ly, adverbnon·al·ter·nat·ing, adjectivequa·si-al·ter·nat·ing, adjectivequa·si-al·ter·nat·ing·ly, adverbun·al·ter·nat·ed, adjectiveun·al·ter·nat·ing, adjective
Can be confusedalternate alternative
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for alternatingly

alternate

verb (ˈɔːltəˌneɪt)

(often foll by with) to occur or cause to occur successively or by turnsday and night alternate
(intr often foll by between) to swing repeatedly from one condition, action, etc, to anotherhe alternates between success and failure
(tr) to interchange regularly or in succession
(intr) (of an electric current, voltage, etc) to reverse direction or sign at regular intervals, usually sinusoidally, the instantaneous value varying continuously
(intr often foll by for) theatre to understudy another actor or actress

adjective (ɔːlˈtɜːnɪt)

occurring by turnsalternate feelings of love and hate
every other or second one of a serieshe came to work on alternate days
being a second or further choice; alternativealternate director
botany
  1. (of leaves, flowers, etc) arranged singly at different heights on either side of the stem
  2. (of parts of a flower) arranged opposite the spaces between other partsCompare opposite (def. 4)

noun (ˈɔːltənɪt, ɔːlˈtɜːnɪt)

US and Canadian a person who substitutes for another in his absence; stand-in

Word Origin for alternate

C16: from Latin alternāre to do one thing and then another, from alternus one after the other, from alter other
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for alternatingly

alternate

adj.

1510s, from Latin alternatus "one after the other," past participle of alternare "to do first one thing then the other; exchange parts," from alternus "one after the other, alternate, in turns, reciprocal," from alter "the other" (see alter). Alternate means "by turns;" alternative means "offering a choice." Both imply two kinds or things.

alternate

v.

1590s, from Latin alternatus, past participle of alternare (see alternate (adj.)). Replaced Middle English alternen "to vary, alternate" (early 15c.). Related: Alternated; alternating.

alternate

n.

1718, "that which alternates (with anything else)," from alternate (adj.). Meaning "a substitute" is first attested 1848.

Online Etymology Dictionary, © 2010 Douglas Harper

alternatingly in Science

alternate

[ôltər-nĭt]

Arranged singly at intervals on a stem or twig. Elms, birches, oaks, cherry trees, and hickory trees have alternate leaves. Compare opposite.
Arranged regularly between other parts, as stamens between petals on a flower.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.