Surface — the last labelled on an icosahedron? (5)
I believe the answer is:
facet
'surface the last labelled on an icosahedron?' is the definition.
'facet' can be an answer for 'surface' (I've seen this before). I'm not certain of the 'the last labelled on an icosahedron?' bit.
'surface the' is the wordplay.
'surface' becomes 'face' (face is a kind of surface).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'face'+'t'='FACET'
Can you help me to learn more?
(Other definitions for facet that I've seen before include "Aspect or feature of something" , "Small surface (of diamond)" , "view" , "Small flat surface of cut gemstone" , "Side or surface, diamond or building" .)