锻炼
duàn liàn
to toughen
to temper; to engage in physical exercise; to work out; (fig.) to develop one's skills; to train oneself
forge metal (锻) + refine by fire (炼) = toughen through training
Smiths forge metal under fire and hammer to make it strong — 锻炼 borrows that image for any process of hardening through effort. 段 and 柬 contribute sound, while the metal and fire radicals carry the meaning.
每天早上跑步可以锻炼身体。
měi tiān zǎo shang pǎo bù kě yǐ duàn liàn shēn tǐ。
Running every morning can work out the body.
多参加实际工作能锻炼你的能力。
duō cān jiā shí jì gōng zuò néng duàn liàn nǐ de néng lì。
Participating more in real work can develop your abilities.