noun
Refers to the act of warming or the state of being warm. Often used in compound words or technical contexts.
暖房で部屋に暖を取る。
I warm the room with the heater.
このスープは体に暖を与える。
This soup gives warmth to the body.
The kanji 暖 is a phono-semantic compound, combining 日 (sun) and 爰 (a phonetic element). The meaning is associated with warmth from the sun.