From Middle Englishbog, from Irish and Scottish Gaelicbogach(“soft, boggy ground”), from Old Irishbog(“soft”), from Proto-Celtic*buggos(“soft, tender”) + Old Irish-ach, from Proto-Celtic*-ākos.
The frequent use to form compounds regarding the animals and plants in such areas mimics Irish compositions such as bog-luachair(“bulrush, bogrush”).
Its use for toilets is now often derived from the resemblance of latrines and outhouse cesspools to bogholes, but the noun sense appears to be a clipped form of boghouse(“outhouse, privy”), which derived (possibly via boggard) from the verb to bog, still used in Australian English. The derivation and its connection to other senses of "bog" remains uncertain, however, owing to an extreme lack of early citations due to its perceived vulgarity.
(Originally Ireland and Scotland) An area of decayed vegetation (particularly sphagnum moss) which forms a wet spongy ground too soft for walking; a marsh or swamp.
a.1513, William Dunbar, Poems:
...Chassand cattell throu a bog...
c.1599, William Shakespeare, The Chronicle History of Henry the Fift, Act III, Scene vii, l. 56:
They that ride so... fall into foule Boggs.
1612, John Speed, The Theatre of the Empire of Great Britaine, Vol. IV, Ch. iv, p. 143:
Certaine... places [in Ireland]... which of their softnes are vsually tearmed Boghes.
(figuratively) Confusion, difficulty, or any other thing or place that impedes progress in the manner of such areas.
1614, John King, Vitis Palatina, p. 30:
...quagmires and bogges of Romish superstition...
a.1796, Robert Burns, Poems & Songs, Vol. I:
Last day my mind was in a bog.
1841, Charles Dickens, Barnaby Rudge, Ch. lxxii, p. 358:
He wandered out again, in a perfect bog of uncertainty.
(uncountable) The acidic soil of such areas, principally composed of peat; marshland, swampland.
a.1687, William Petty, Political Arithmetick:
Bog may by draining be made Meadow.
(UK, Ireland, Australia and New Zealand, slang) A place to defecate: originally specifically a latrine or outhouse but now used for any toilet. For example "I’m on the bog" - I’m sitting on/using the toilet; "I’m in the bog" - I’m in the bathroom; "I flushed it down the bog".
1665, Richard Head & al., The English Rogue Described in the Life of Meriton Latroon, Vol. I:
Fearing I should catch cold, they out of pity covered me warm in a Bogg-house.
a.1789, in 1789, Verses to John Howard F.R.S. on His State of Prisons and Lazarettos, p. 181:
...That no dirt... be thrown out of any window, or down the bogs...
1864, J.C. Hotten, The Slang Dictionary, p. 79:
Bog, or bog-house, a privy as distinguished from a water-closet.
1959, William Golding, Free Fall, Ch. i, p. 23:
Our lodger had our upstairs, use of the stove, our tap, and our bog.
(Australia and New Zealand, slang) An act or instance of defecation.
(US, dialect) A little elevated spot or clump of earth, roots, and grass, in a marsh or swamp.
(wet spongy areas or ground):bogg, bogge, boghe(all obsolete)
From Proto-Germanic*bōguz. Cognate with Old Saxonbōg, Dutchboeg(“shoulders, chest of a horse”), Old High Germanbuog (GermanBug(“horse’s hock, ship’s prow”)), Old Norsebógr (Icelandicbógur, Swedishbog(“shoulder”)).
IPA(key): /boːɡ/, [boːɣ]
a branch or bough of a tree
the arm or shoulder
From Old Irishboc(“soft, gentle, tender; tepid”).
wet, damp, moist
Edward Dwelly (1911), “bog”, in Faclair Gàidhlig gu Beurla le Dealbhan [The Illustrated Gaelic–English Dictionary], 10th edition, Edinburgh: Birlinn Limited, →ISBN
Gregory Toner, Maire Ní Mhaonaigh, Sharon Arbuthnot, Dagmar Wodtko, Maire-Luise Theuerkauf, editors (2019), “1 boc”, in eDIL: Electronic Dictionary of the Irish Language
bȏgm (Cyrillic spellingбо̑г)
(colloquial) idol, god
bȍgovskī / bogòvskī
Walter Breu and Giovanni Piccoli (2000), Dizionario croato molisano di Acquaviva Collecroce: Dizionario plurilingue della lingua slava della minoranza di provenienza dalmata di Acquaviva Collecroce in Provincia di Campobasso (Parte grammaticale)., pp. 394
bọ̑gm anim (female equivalentbogínja)
“bog”, in Slovarji Inštituta za slovenski jezik Frana Ramovša ZRC SAZU, portal Fran
From Old Swedishbōgher, from Old Norsebógr, from Proto-Germanic*bōguz, from Proto-Indo-European*bʰāǵʰus.