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.
Well to you he would be your cousin
To your father it would be his nephew.
Any of your mother's sisters - are your aunties.
In Tamil, elder sister is called "அக்கா" (Akka).
"Sister" in Tamil is called "சகோதரி" (Sakothari) for an elder sister and "சிச்டர்" (Sister) for a younger sister.
Your brother's wife is your sister-in-law.
sister in law
noona for elder sister 누나- that is how you right it
You would call your wife's elder brother's wife "sister-in-law."
cousin
In Malayalam, 'sister' means 'Sahodhari'. (Chechy = elder sister, Anujathy = younger sister)
Sister-in-Law
sister in law
Sister In law
Mom