one of an order of nuns founded by st. angela merici, at brescia, in italy, about the year 1537, and so called from st. ursula, under whose protection it was placed. the order was introduced into canada as early as 1639, and into the united states in 1727. the members are devoted entirely to education.-of or pertaining to st. ursula, or the order of ursulines; as, the ursuline nuns.