Translation:This wall is green.
I thought diwar could be used to describe a door?
Nope. Door is called दरवाज़ा (darwaazaa).
I thought its "this wall is in green colour"
I guess its correct
is wall masculine or feminine ? Duo says: दीवार हरी है but plural is दीवारै, correct ?
दीवारें is the plural, which is the plural for feminine nouns not ending in ई, it is feminine.