In a white area, it stains brown (3)
I believe the answer is:
tea
'stains brown' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'in a white area it' is the wordplay.
'in' says the answer is hidden in the clue.
'TEA' can be found hidden inside 'white area it'.
Can you help me to learn more?
(Other definitions for tea that I've seen before include "Light afternoon meal" , "Afternoon meal; drink" , "tips for the cup?" , "Cuppa" , "Beverage; meal" .)