"All" refers to the totality of a group or category, encompassing every individual or element within it. It signifies completeness and inclusivity, meaning nothing is left out. For example, when we say "all animals," we are referring to every species, from cats to elephants. In mathematics, "all" can represent a universal set, which includes every possible member of a defined category. In logic, it is often used in statements like "All humans are mortal," indicating that every member of the group shares a common characteristic.