hot stone; heated stone
A stone that has been heated, often used in cooking, sauna, or traditional practices. Also appears in the proverb 焼け石に水 (a drop in the bucket).
Grill meat on a hot stone.
When you pour water on a hot stone, it sizzles.
Compound of 焼け (yake, 'burning, heated') + 石 (ishi, 'stone'). The reading やけいし is a straightforward combination.