Определение/значение underfiring

• English - Noun: underfiring ( uncountable ) Heating from below . ( Also used attributively . ) Intentional operation of a boiler , furnace , oven , etc . , at a low level . The state of not burning fuel at the desired level , and thus not providing heat efficiently . ( ceramics ) The state of being insufficiently fired or underfired .
• English - Verb: underfiring Present participle of underfire .
• English - Antonyms: overfiring
• English - Etymology: under- +‎ firing