Your mom's elder sister is your aunt; the son of your aunt is your cousin, and the daughter of your cousin is your cousin once removed.
In Tamil, elder sister is called "அக்கா" (Akka).
akka .. for elder thangai for younger
Your brother's wife is your sister-in-law.
sister in law
noona for elder sister 누나- that is how you right it
While generally referred to as a Sister-in-law, there is no relationship.
cousin
Sister-in-Law
sister in law
Sister In law
Mom
In Hindi, you would call your mother's sister "mausi" or "masi".