on all fours Definition

four
noun

1a. The cardinal number 4;
1b. The quantity that this represents, being one more than three.
2. Any symbol for this, eg 4 or IV.
3. The age of four.
4. Something, especially a garment, or a person, whose size is denoted by the number 4.
5. The fourth hour after midnight or midday.

Example: Tea's at four
Example: 4 o'clock
Example: 4pm
6. A set or group of four people or things.
7a. The crew of a rowing boat with four sweep oars;
7b. Such a boat.
8. A playing-card with four pips.
9. A score of four points.
10. cricket.
A score of four runs awarded if the ball reaches the boundary having hit the ground.

adj

1. Totalling four.
2. Aged four.

Idiom: on all fours

On hands and knees.

Etymology: Anglo-Saxon feower.