The word "cannon" (a large, heavy piece of artillery) can remain unchanged in its plural form, especially when referring to a group of them collectively. However, "cannons" is also accepted.

১. "Criterion" is singular; its plural form is "criteria".
২. "Light" and "shot" change their meaning or form significantly when used as countable/uncountable nouns.
৩. Words like "sheep", "deer", and "fish" are more common examples of this category.

অতিরিক্ত তথ্য: Nouns with the same singular and plural form are called "zero plurals."