1. A game at cards, so called from the chance of four honours which it offers. On all fours, on legs and arms.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• zll fours,
• sll fours,
• wll fours,
• qll fours,
• akl fours,
• apl fours,
• aol fours,
• alk fours,
• alp fours,
• alo fours,
• all dours,
• all cours,
• all vours,
• all gours,
• all tours,
• all rours,
• all fiurs,
• all fkurs,
• all flurs,
• all fpurs

The adjective form of "all fours" is "quadrupedal".

The plural form of "all fours" remains the same, as it is already plural.

The singular form of "all fours" is "all four".