Sin means 'that, those';
Sín means 'stretch; hold out; lengthen; extend'
that's it!
"Mar sin é" means "Is that so?"
Irish is a language more complex than English. You have to learn it.
"Music and dance and chat." in Irish.
Céard faoi sin.
sin-seanathair
sin iontas
bulfnan
Cé hé an gasúr sin?
An bhfeiceann tú é sin?
Cá bhfuil an bhialann sin?
In Irish it's "sin uile"