The Collaborative International Dictionary
Tail-bay
Tail-bay \Tail"-bay`\, n.
(Arch.) One of the joists which rest one end on the wall and the other on a girder; also, the space between a wall and the nearest girder of a floor. Cf. Case-bay.
The part of a canal lock below the lower gates.
Wiktionary
tail-bay
n. 1 (context architecture English) One of the joists which rest one end on the wall and the other on a girder. 2 (context architecture English) The space between a wall and the nearest girder of a floor. 3 The part of a canal lock below the lower gates.