1.
pork bone; tonkotsu broth
Pork bones, or the rich, milky-white broth made by boiling pork bones for many hours. Most commonly associated with ramen.
Etymology
豚 (pork) + 骨 (bone). Uses on'yomi readings for both characters.
Usage
豚骨 most commonly appears in the context of ramen. 豚骨ラーメン originated in 博多 (福岡) and is now one of Japan's most popular ramen styles. The broth is characteristically cloudy white from the collagen and fat rendered during extended boiling.