[se]

1. feminine noun The letter s.

-s

1. derivative suffix Added to a singular noun, adjective or pronoun, it changes the number to plural.

Spelling: When the singular word ends in a specic letter, such as -c, -f, -gg, -ix, -ll, -nn, -s, -z, the plural is made by adding -es instead of -s.

Etymology: From Latin -os, -as (accusative plural markers).