British. (on a road or railroad) a place beside the main road or track where vehicles may wait.
2.
Nautical. a mooring place in a narrow river or canal, formed to one side so as to leave the channel free.
Origin
1795-1805; noun use of verb phrase lay by
British Dictionary definitions for lay-by
lay-by
noun
1.
(Brit) a place for drivers to stop at the side of a main road
2.
(nautical) an anchorage in a narrow waterway, away from the channel
3.
a small railway siding where rolling stock may be stored or parked
4.
(Austral & NZ, South African) a system of payment whereby a buyer pays a deposit on an article, which is reserved for him until he has paid the full price
verb (adverb)
5.
(transitive) to set aside or save for future needs
6.
Also lay to. to cause (a sailing vessel) to stop in open water or (of a sailing vessel) to stop