Surrounded by mangos, possibly tons (7)
I believe the answer is:
amongst
'surrounded by' is the definition.
(I've seen this before)
'mangos possibly tons' is the wordplay.
'possibly' indicates an anagram.
'tons' becomes 't'.
'mangos' anagrammed gives 'amongs'.
'amongs'+'t'='AMONGST'
(Other definitions for amongst that I've seen before include "Within the group of" , "Famous novel by John McGahern: '... Women'" , "Amid" , "Having been absorbed, perhaps" , "In the midst of" .)