You're welcome.
The difference is roughly this:
"Nuns" live in a cloistered community, carrying out their vocation relatively isolated from the secular world. The nuns of St. Jude Monastery are an example
"Sisters" (should) live in community, but carry out their vocation in direct contact with the secular world. The "Missionaries of Charity", founded by Mother Teresa, are an example.
The older I become, the more I realize how little I know...
So, all those years in Catholic school, when everyone was referring to the sisters as both “sisters” and “nuns,” we were confusing two terms with one another. I’m just curious: If the title “Sister” (as in Sister Mary Margaret) is used for sisters, is there a different title used for nuns?