Computer in battle ground (6)
I believe the answer is:
tablet
'computer' is the definition.
(I know that tablet is a type of mobile computer)
'battle ground' is the wordplay.
'ground' indicates an anagram ('grind' the letters into a new form).
'battle' with letters rearranged gives 'TABLET'.
'in' is the link.
(Other definitions for tablet that I've seen before include "pill needed" , "Small bar of soap" , "PC" , "Pill; writing pad" , "Weekly" .)