Definition of "lay down"

lay down

verb
third-person singular simple present lays down, present participle laying down, simple past and past participle laid down
1. (transitive) To give up, surrender, or yield (e.g. a weapon), usually by placing it on the ground.
2. To place on the ground, e.g. a railway on a trackbed.
  Quotations
  He also thought nothing of laying down a railway in a war zone. For example, he was one of those behind the Grand Crimean Central Railway, built during the Crimean War [...].
  2021 December 29, Stephen Roberts, “Stories and facts behind railway plaques: Chester (1848)”, in RAIL, number 947, page 57
3. (transitive) To intentionally take a fall while riding a motorcycle, in order to prevent a more serious collision.
4. (transitive) To specify, institute, enact, assert firmly, state authoritatively, establish or formulate (rules or policies).
  Quotations
  Well, I lay it down, first, that a book quite unornamented can look actually and positively beautiful, and not merely un-ugly, if it be, so to say, architecturally good, which, by the by, need not add much to its price […]
  1893, William Morris, The Ideal Book
  Many of the faults reported in all categories should have been cleared by systematic fault-finding. Once a system of fault-finding has been laid down, staff must be made familiar with it and must follow the correct sequence of diagnosis step by step in the way set out in a fault-finding chart.
  1963 February, “Diesel locomotive faults and their remedies”, in Modern Railways, page 103
  The law was written in words, and those ideally laid down bright lines for everyone to follow
  2016 February 20, “Obituary: Antonin Scalia: Always right”, in The Economist
5. To stock, store (e.g. wine) for the future. See also lay by.
6. (euphemistic, transitive) To euthanize an animal.
7. To sacrifice, especially in the phrase "to lay down one's life."
8. (intransitive, nonstandard, proscribed) To lie down; to place oneself in a reclined or horizontal position, on a bed or similar, for the purpose of resting.
9. (nautical, dated) To draw the lines of a ship's hull at full size, before starting a build.
verb
1. simple past of lie down