leaf

1. (botany) A foliage leaf or any of the many and often considerably different structures it can specialise into.countableuncountable

2. (publishing, bookbinding, advertising) A sheet of a book, magazine, etc. (consisting of two pages, one on each face of the leaf).Examples: "Heretofore advertisers have had to buy and pay for a leaf — two pages."countableuncountable

3. (in the plural) Tea leaves.countablein-pluraluncountable

4. (plural leaves or leafs) A moveable panel, e.g. of a bridge or door, originally one that hinged but now also applied to other forms of movement.Examples: "The train car has one single-leaf and two double-leaf doors per side."; "The bridge shear locks were repaired and the long ends of the shear locks shortened about two inches to eliminate butting of the bridge leafs against each other."; "It will be noted that the pivotal mounting of the cylinders is such that the cylinders have their greatest leverage (i.e., exert the greatest door-opening force) when the door leafs 24, 28 are closed because the cylinders are generally perpendicular to the closed leafs. This is desirable because the load on the leafs is the greatest when they are closed due to air pressure. As the leafs begin to open and this air pressure decreases, the opening force exerted by the cylinders on the door leafs decreases and the opening speed of the leafs increases."countableuncountable

5. (computing, mathematics) In a tree, a node that has no descendants.Examples: "The algorithm pops the stack to obtain a new current node when there are no more children (when it reaches a leaf)."countableuncountable

6. (slang, uncountable) Cannabis.slanguncountable