Duality

How to spell duality

7 letters · 4 syllables

How to pronounce duality

Say the part in capitals loudest.

What does duality mean?

1. nounThe state of having two often contrasting parts, natures, or aspects.

Duality in a sentence

• The novel explores the duality of its hero, who is gentle at home and ruthless at work.

• Physics students struggle with the wave-particle duality of light.

Where does duality come from?

Language of origin: Latin

The word traces back to the Latin duo, meaning simply 'two', from which Latin formed the adjective dualis, 'containing two' or 'of a pair'. By the late medieval period this had given the Late Latin noun dualitas, describing the condition of being twofold, and English took it up through French as 'duality' in the fifteenth century. The sense has always centred on two parts coexisting, whether two natures, two forces, or two opposing aspects within one thing. The same duo root sits behind a whole family of English words such as 'dual', 'duel', 'duet', 'duo', and even 'double', so anyone who can hold that 'two' meaning in mind has a reliable anchor for the spelling. The trap is purely the unstressed middle: the stress lands on the second syllable, leaving the rest as faint schwa sounds that tempt writers to drop or scramble letters.

How the word is built

• du- (from Latin duo: two)
• -al (adjective suffix)
• -ity (noun-forming suffix: state or quality)