summer melt
n.— «By late spring, millions of high-school seniors have mailed in deposits to confirm their college destinations. Some of these “confirmations,” however, will be broken. A student will be belatedly admitted to a school he prefers; a family will re-examine its college nest egg and judge it too small for a tuition omelet; little Jack will decide he would rather spend the year hitchhiking the Maghreb from Marrakesh to Mahdia. The folks who work in admissions call these defections “the summer melt.”» —“Summer Melt” by Peter Wood National Review Online June 27, 2001. (source: Double-Tongued Dictionary)