Incorrect spelling, explanation: when it comes to forming a plural form of a noun leaf, many people make the mistake of simply adding the -s ending to it, which results in leafs. That form, however, is incorrect as according to the rule when a singular noun ends in -f or -fe, we need to change it to -v and then add -es, which gives the correct plural form leaves.

Correct spelling, explanation: leaves is a word with a long history as it already appeared in Old English after it came from Old Germanic. Leaves is a plural noun and its singular form is leaf. It’s important to notice that we don’t form a plural form only by adding -s to the singular noun, but by changing -f to -v and then adding -es.

Definition of leaves:
1. noun – plural of leaf, refers to a green, usually flat part of a tree or plant; it can also refer to thin paper layers:
The leaves of that plant may look beautiful, but they contain a poisonous substance.
The leaves of that old book are almost completely destroyed so be careful with that.

Expressions with leaves:
Some typical expressions with the word include falling leaves, colorful leaves, and lettuce leaves. The word often goes together with the verbs: turn, fall, appear.
Look at all those beautiful, falling leaves.
The whole park is covered with wonderful, colorful leaves.
Take those lettuce leaves and tear them into the salad bowl.
The summer is almost over and the leaves start to turn.
In such a windy day the leaves are falling everywhere.
It’s finally March and green leaves already appear on the trees.