Solid may drip when melted (7)
I believe the answer is:
pyramid
'solid' is the definition.
(type of geometric solid)
'may drip when melted' is the wordplay.
'when melted' indicates anagramming the letters.
'may'+'drip'='maydrip'
'maydrip' is an anagram of 'PYRAMID'.
(Other definitions for pyramid that I've seen before include "Giza monument" , "Egyptian monument" , "ancient monument" , "Type of polyhedron" , "A 3D shape" .)