on all fours

• on all-fours

on all fours (not comparable)

1. (idiomatic) On one's hands and knees.
   • 1916, Elbert Hubbard, Little Journeys Vol. 14: Great Musicians, "Johannes Brahms":

     He was on all fours, with three children on his back, riding him for a horse.

2. (idiomatic, often followed by "with") Similar in nature or effect to something else; consistent.
   • 1920, Rudyard Kipling, Letters of Travel, ch. 21:

     The new law was precisely on all-fours with the Homestead Act.

on all fours (not comparable)

1. (idiomatic) On one's hands and knees.
   • 1897, Joseph Conrad, The Nigger Of The ‘Narcissus’, ch. 3:

     A bulky form was seen rising aft, and began marching on all fours with the movements of some big cautious beast.

2. (idiomatic, often followed by "with") In a manner which is similar in nature or effect to something else; consistently.
   • 1887, Thomas Hardy, The Woodlanders, ch. 39:

     The paternal longing ran on all fours with her own desire.

• all fours

• quadrupedal, quadrupedally