Balance is another common word that can be easily missed as the ancient prefix -bi is not longer discernible in the word. English borrowed it from French balance in the thirteenth century with the meaning "uncertainty, risk, hazard, doubt, wavering" and the meaning "weighing scales" came later. Today, it has many figurative and other senses not related to "two". It is originated from Latin bilanx meaning two-scaled.

The etymology of balance from OED:

< French balance (= Spanish balanza, Provençal balansa, Italian bilancia) < late Latin bilancia a pair of scales, < classical Latin bilanx, bilanc-em, adjective (in libra bilanx) ‘two-scaled,’ < bi- twice + lanx flat plate, scale.

Note: The French word balance might have been altered with false analogy from ballant (dangling, hanging) or ballare (to dance). The proper form is retained in the word bilan (balance-sheet) where French borrowed from Italian bilancio.

Balance is another common word that can be easily missed as the ancient prefix -bi is no longer discernible in the word. English borrowed it from French balance in the thirteenth century with the meaning "uncertainty, risk, hazard, doubt, wavering" and the meaning "weighing scales" came later. Today, it has many figurative and other senses not related to "two". It is originated from Latin bilanx meaning two-scaled.

The etymology of balance from OED:

< French balance (= Spanish balanza, Provençal balansa, Italian bilancia) < late Latin bilancia a pair of scales, < classical Latin bilanx, bilanc-em, adjective (in libra bilanx) ‘two-scaled,’ < bi- twice + lanx flat plate, scale.

Note: The French word balance might have been altered with false analogy from ballant (dangling, hanging) or ballare (to dance). The proper form is retained in the word bilan (balance-sheet) where French borrowed from Italian bilancio.