Plant rice over area (5)
I believe the answer is:
erica
'plant' is the definition.
The answer is an example.
'rice over area' is the wordplay.
'over' indicates an anagram.
'area' becomes 'a' (maths abbreviation).
'rice' anagrammed gives 'eric'.
'eric'+'a'='ERICA'
(Other definitions for erica that I've seen before include "Moorland plant, girl's name" , "Heath genus; girl's name" , "Girl - heather" , "I care about Heather, oddly" , "I care (anag) - plant - girl" .)