fire bed; fire grate; hearth
Refers to the part of a stove, furnace, or traditional hearth where the fire is built and burns; a technical or somewhat literary term.
鍛冶屋は火床で鉄を熱した。
The blacksmith heated the iron on the fire bed.
古いストーブの火床に薪をくべる。
Put firewood on the fire grate of the old stove.
Compound of 火 (hi, 'fire') and 床 (doko, 'bed' or 'floor'), literally 'fire bed'. The reading ひどこ is a straightforward combination of the kun'yomi readings of the two kanji.