See also: カイロ and がいろ

Japanese edit

For pronunciation and definitions of かいろ – see the following entries.
回路
[noun] any circuit in which energy or matter moves in a cycle, such as an electrical circuit
懐炉
[noun] bosom-warmer; body-warmer
[noun] (by extension) handwarmer
Alternative spelling
カイロ
(This term, かいろ, is the hiragana spelling of the above terms.)