Fruit also covers rug (6)
I believe the answer is:
tomato
'fruit' is the definition.
(type of fruit)
'also covers rug' is the wordplay.
'also' becomes 'too' (synonyms).
'covers' indicates putting letters inside.
'rug' becomes 'mat' (I've seen this before).
'too' placed around 'mat' is 'TOMATO'.
(Other definitions for tomato that I've seen before include "Shiny red fruit" , "Salad plant" , ""Plum" or "beef" fruit?" , "Pulpy edible fruit" , "A glossy red fruit eaten as a vegetable" .)