Vail, n. [Aphetic form of avail, n.]
1. Avails; profit; return; proceeds.
My house is as 'twere the cave where the young outlaw hoards the stolen vails of his occupation. Chapman.
2. An unexpected gain or acquisition; a casual advantage or benefit; a windfall.
3. Money given to servants by visitors; a gratuity; — usually in the plural. [Written also vale.] Dryden.