noun
cavity; hollow; pore; bubble; blowhole
Refers to small internal voids or air pockets, especially in old root vegetables (like daikon), tofu, metal castings, or similar materials. Often used in cooking and manufacturing contexts.
この大根はすが入っていて、味が落ちている。
This daikon has cavities inside, so the flavor is worse.
鋳物にすがあると強度が下がる。
If there are blowholes in the casting, the strength decreases.
noun which may take the genitive case particle 'no'
Describes a texture or structure full of small holes, like a sponge or pithy vegetable. Used attributively with の.
すの入った大根は煮物に向かない。
A spongy daikon is not suitable for simmered dishes.
空洞 is a general term for a hollow or cavity, while す specifically refers to small, often undesirable internal voids in food or materials.
気泡 means air bubble in a liquid or solid, but す implies a structural defect or natural sponginess rather than just a bubble.
The origin is uncertain. The kanji 鬆 is a rare character used specifically for this meaning, but the word itself is native Japanese.