Practice JLPTMeaning
数の子 (かずのこ, Kazunoko) is Herring roe — a Japanese food (fish eggs, ingredients).
What is Herring roe?
Kazunoko is herring roe (caviar). It is yellow or pinkish, having a firm, rubbery texture and appearance, and usually is pickled. The roe is in a single cohesive mass and so looks like a piece of fish. It sometimes is written "鯑".