'偶数' (ǒu shù) literally combines 偶 (ǒu), meaning 'even' or 'paired', and 数 (shù), meaning 'number'. Together, they form the mathematical term for any integer divisible by two without remainder — such as 0, 2, 4, −6, or 100. In Chinese, this word is used exclusively in formal, academic, or technical contexts like mathematics, programming, logic puzzles, or standardized tests.

Unlike English, where 'even number' can appear in casual speech ('Pick an even number!'), 偶数 is rarely used in everyday conversation outside educational or analytical settings. It contrasts directly with 奇数 (jī shù), meaning 'odd number', and both terms are fundamental in number theory, parity checks, and algorithm design. Students encounter 偶数 early in primary math curricula, often alongside visual aids like grouping objects into pairs to demonstrate divisibility by two.