The Collaborative International Dictionary of English v.0.48:
Fleet \Fleet\, n. [AS. fle['o]t a place where vessels float,
bay, river; akin to D. vliet rill, brook, G. fliess. See
Fleet, v. i.]
1. A flood; a creek or inlet; a bay or estuary; a river; --
obsolete, except as a place name, -- as Fleet Street in
Together wove we nets to entrap the fish
In floods and sedgy fleets. --Matthewes.
2. A former prison in London, which originally stood near a
stream, the Fleet (now filled up).
Fleet parson, a clergyman of low character, in, or in the
vicinity of, the Fleet prison, who was ready to unite
persons in marriage (called Fleet marriage) at any hour,
without public notice, witnesses, or consent of parents.