Definition of "knock down"

knock down

verb
third-person singular simple present knocks down, present participle knocking down, simple past and past participle knocked down
1. (transitive) To hit or knock (something or someone), intentionally or accidentally, so that it falls.
  Quotations
  He was out tomcatting one night / When he started a big fight / And a big policeman came and knocked him down.
  1977, Sonny James (lyrics and music), “In the Jailhouse Now”, in Sonny James In Prison, In Person‎
  I won't surrender / I will fight better / You lock me out, you knock me down / But I will find my way around
  2012, Ingrid Michaelson (lyrics and music), “This Is War”, in Human Again‎
2. (transitive) To demolish.
3. (transitive) At an auction, to declare (something) sold with a blow from the gavel.
4. (transitive, informal) To reduce the price of.
5. (transitive, informal) To drink fast.
6. (transitive, usually passive voice) To disassemble for shipment.
7. (transitive) To approve a drinking toast by banging glasses on the table.
  Quotations
  They click their glasses and knock down the toast.
  1954, H. C. N. de Lanerolle, "Well, Mudaliyar!" and Other Plays (page 179)