How to Write 衍 (yǎn) — Meaning “To develop or spread”

Imagine 'water' (冫) 'walking' (行) through a field — the water spreads and develops into streams everywhere. The idea of water moving along a path helps you recall that 衍 means 'to develop or spread.'

Write the left radical 行 first: left side 彳 (two strokes), then right side 亍 (three strokes), but note that 衍 actually uses the full radical 行 as the left component, so you write all strokes of 行 before adding the right side. The right side 氵 (three dots) is replaced by 冫 (two dots) here — be careful not to add a third dot. Keep the two dots small and aligned vertically near the top-right of the character.

衍 (yǎn) has 行 on the left and 冫 (two dots) on the right, while 衔 (xián) has 行 on the left and 金 (jīn, 'gold/metal') on the right. Visually, 衍's right side is two dots (like water), whereas 衔's right side is a complex component with multiple strokes. Their meanings are also different: 衍 relates to spreading and deriving, while 衔 means 'to hold in the mouth' or 'rank.'

衍 appears in common words like 衍生 (yǎn shēng, 'to derive') in science and 繁衍 (fán yǎn, 'to multiply') for population increase. It is also used in 敷衍 (fū yǎn, 'to be perfunctory'), which originally meant 'to spread out' but now describes doing something carelessly. This character is not in HSK but is important for academic and formal writing.

Common words containing 衍 include: 衍生 (yǎn shēng) — To derive; 繁衍 (fán yǎn) — to multiply or propagate; 敷衍 (fū yǎn) — to be perfunctory; to go through the motions.