noun
rock candy; sugar candy; crystallized sugar
Refers to large, clear sugar crystals often used in cooking, preserves, or as a sweet treat. The term is neutral and common.
梅酒を作るときに氷砂糖を使います。
I use rock candy when making plum wine.
Compound of 氷 (こおり, 'ice') and 砂糖 (さとう, 'sugar'), referring to sugar crystals that resemble ice.