Hot soil in fireplace (6)
I believe the answer is:
hearth
'fireplace' is the definition.
(synonyms)
'hot soil' is the wordplay.
'hot' becomes 'h' (abbreviation eg on taps).
'soil' becomes 'earth' (I've seen this before).
'h'+'earth'='HEARTH'
'in' acts as a link.
(Other definitions for hearth that I've seen before include "cosy setting" , "suitable place for a fire" , "home circle" , "Fireplace surround" , "part of furnace" .)