• (RP) IPA: /fəʊ/
• (America) IPA: /foʊ/

From Middle English fo, from earlier ifo ("foe"), from Old English ġefāh, from fāh ("hostile"), from Proto-West Germanic *faih, from Proto-Germanic *faihaz (compare ofs fāch, Middle High German gevēch), from Proto-Indo-European *peyḱ- (compare Middle Irish óech, Lithuanian pìktas).

foe

1. (obsolete) Hostile.
   • 1603, Michel de Montaigne, translated by John Florio, The Essayes […], London: […] Val[entine] Simmes for Edward Blount […], →OCLC ↗:
     , vol.1, ch.23:

     he, I say, could passe into Affrike onely with two simple ships or small barkes, to commit himselfe in a strange and foe countrie, to engage his person, under the power of a barbarous King […].

• German: gegnerisch, feindlich
• Spanish: rival

foe (plural foes)

1. An enemy.

• (enemy) adversary, enemy, opponent, fiend.

• (antonym(s) of “enemy”): ally, friend

Acronym of [ten to the power of] fifty-one ergs due to equalling 10⁵¹ ergs; coined by Gerald Brown of Stony Brook University in his work with Hans Bethe.

foe (plural foes)

1. A unit of energy equal to 10⁴⁴ joules.

• bethe (B)

1. Initialism of Friends of the Earth

1. Initialism of Friends of the Earth
2. Initialism of Fraternal Order of Eagles

foe (uncountable)

1. Initialism of freedom of expression
2. Initialism of forces of evil