I think this may depend on the particular religious order.
I spent some years as a Discalced Carmelite (same order as St Therese, St Teresa and St John of the Cross), and all the nuns throughout the world (as far as I know) called their place a monastery.
Maybe it denotes an enclosed, contemplative order.
“Nun”, by the way, refers only to a member of a contemplative order who takes solemn vows (as opposed to perpetual vows) for their final profession. Don’t ask me to explain the difference!
Members of active orders are “sisters”, not “nuns” in the strict sense of the word, as understood by the Catholic Church.
Of course, nuns refer to each other as “Sisters” and can be called sisters by anyone - I’m just referring to the “official” definition of what a nun is!