noun

duality

doo-AL-uh-tee/duːˈæləti/

A paired structure with two corresponding aspects.

The landscape and its reflection create a duality above and below the water.

One landscape reflected in still water, two distinct joined aspects, above and below clearly visible.

Etymology

duLatintwo

+alLatinrelating to

+ityLatinstate or quality

The endings turn “two” into a quality or state: being twofold. Duality therefore names the condition of having two parts or aspects, rather than the parts themselves.

In context

The Scroll of Shadows24:22

On one hand, a creature of brutal combat, on the other, a symbol of communal sustenance. This duality made the boar irresistible

25 Stunning Heraldry Designs and the Meaning Behind Knightly Symbols | Medieval History Guide

More examples

Her stern manner and gentle actions reveal a striking duality.
Light exhibits wave-particle duality.
This duality lets mathematicians translate results between the two theories.

Forms

duality · dualities

dual adjective — Having two parts, aspects, or functions.

Similar words

dichotomy: Emphasizes division into two sharply opposed categories or parts.
polarity: Emphasizes opposition between two extremes rather than paired correspondence.