To lessen the extent to which someone controls, influences, or monitors someone else, especially parents in relation to their children. Mothers these days are so fussy about their kids, having to know where they are at every second of the day. They would really do well to loosen the apron strings a little, if you ask me! Sending kids to summer camps has been in decline in recent years, as parents have become less and less inclined to loosen the apron strings.