also: ほねあぶら
noun
bone oil; clarified bone stock
Refers to oil or fat rendered from bones, used in cooking or industrial contexts. こつゆ is the standard reading; ほねあぶら is rare.
ラーメンのスープには骨油が使われている。
Bone oil is used in ramen broth.
骨油を抽出する工程は手間がかかる。
The process of extracting bone oil is labor-intensive.
Compound of 骨 (bone) and 油 (oil). The reading こつゆ uses the on'yomi of 骨, while ほねあぶら uses the kun'yomi. The exact historical derivation is uncertain, but the term is straightforwardly descriptive.