練

It is a compound ideograph, formed from:

糸 (thread, silk) – semantic element, referring to silk threads.

柬 (gan, “to choose, to select”) – indicating the action of selecting.

The original sense was “to boil selected silk threads (from cocoons) in hot water to refine them.” When raw silk was boiled and treated, it became softer and whiter. From this process, the figurative meaning of “to refine, to practice, to train” developed.

Etymological note: 練 originally refers to silk being refined, while 鍊 (to temper metal) refers to smelting or refining metal. Over time, however, the two characters were sometimes interchangeably used in the extended sense of “to practice, to temper, to train.”

In Korean, 련 (練) appears in many compounds related to practice and training:

연습 (練習) – practice, rehearsal

단련 (鍛練/鍛鍊) – training, discipline

훈련 (訓練) – training, drill

연마 (硏練) – polishing, refinement

숙련 (熟練) – skilled, experienced

Note the difference in the right-side component between traditional Chinese (柬) and Japanese shinjitai (東).

Three CJK compatibility ideographs exists for this code point. Among them, U+FA57 corresponds to the Japanese kyūjitai form of this character.