double-u

noun3

1. •
   The name of the Latin script letter W/w.
2. •
   (euphemistic) The WC; the toilet.

   • She would try the front door, and try the back door, and look in the windows; and once she even looked in the double-u. — 1974
3. •
   Alternative name of the Latin-script digraph ⟨UU⟩.

noun1

1. •
   something in the shape of two U's (not of a W)

   • In training a tree in the double U […] only the two topmost buds are allowed to grow on the trunk and two arms. — 1942