a bout of work; a spell of exertion; working up a sweat
Refers to doing a task or physical activity that makes one sweat, often used in the phrase 一汗かく (to work up a sweat). The second gloss about riding a horse is a specific historical example of such exertion.
Let's work up a sweat this morning.
庭仕事で一汗かいた。
I worked up a sweat doing yard work.
Standard kanji spelling for this noun.
Mixed kana-kanji spelling commonly seen in modern writing.
Compound of 一 (one) and 汗 (sweat), literally 'one sweat'. The exact historical derivation is uncertain, but it has been used to refer to a single bout of sweaty exertion.