衰变 (shuāi biàn) — to decay (in physics, e.g. radioactive decay)

Definition

A physics term meaning radioactive decay — the spontaneous breakdown of an unstable atomic nucleus releasing radiation. Distinguish from the more general verb 衰减 (shuāi jiǎn), which covers any weakening or loss (signal, intensity, quality).

verb
to decay (in physics, e.g. radioactive decay)

Examples

  • 衰变。
    Fàng shè xìng yuán sù huì shuāi biàn.
    Radioactive elements can decay.
  • 衰变。
    Zhè ge yuán zǐ hé zhèng zài shuāi biàn.
    This atomic nucleus is decaying.
  • 衰变。
    Kē xué jiā yán jiū shuāi biàn guò chéng yǐ yǒu duō nián.
    Scientists have been studying the decay process for many years.

Origin

Compound word
构词法gòucífǎ
偏正piānzhèngModifier + head

The first part narrows down the second: it says what kind of thing the head is.

衰shuāidecline
变biànchange

衰 means decline and 变 means change; 衰变 is the change of decaying.

Characters in this word

A drawing of the thing itself, worn down over three thousand years into a few strokes.

The old form of 衰 pictures a palm-fiber raincoat, a garment later written with another character.

Open 衰 →

Most characters — around four in five — are built this way: one part hints at the meaning, the other at the pronunciation.

This origin belongs to the traditional form 變; 变 is its simplified writing.

Meaning part形符xíngfú
攴攴pū
Sound part声符shēngfú
䜌
䜌䜌變biàn
The sound has drifted apartThe sound part was a clue two thousand years ago — it often still helps, but not always.

The traditional form 變 uses 䜌 as a sound part and 攴 as a meaning part.

Open 变 →

Browse more HSK 7-9 words or search the full 43,000-word dictionary.