Mere elk roaming around area (4)
I believe the answer is:
lake
'mere' is the definition.
(I've seen this before)
'elk roaming around area' is the wordplay.
'roaming' indicates an anagram.
'around' means one lot of letters goes inside another.
'area' becomes 'a' (maths abbreviation).
'elk' is an anagram of 'lke'.
'lke' enclosing 'a' is 'LAKE'.
(Other definitions for lake that I've seen before include "Purplish-red pigment" , "Superior maybe < that's red" , "holiday up north" , "E.g. Huron" , "Mere, tarn" .)