Eruption from Earth's mantle (6)
I believe the answer is:
escape
'eruption' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'earth's mantle' is the wordplay.
'earth's' becomes 'E's'.
'mantle' becomes 'cape' (synonyms).
'es'+'cape'='ESCAPE'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for escape that I've seen before include "Computer key" , "issue" , "Manage to avoid" , "has to fly" , "find way out" .)