"Pulrals" appears to be a typographical error or a misinterpretation. If you meant "plurals," they refer to the grammatical form of a noun that indicates more than one person, animal, thing, or concept. In English, plurals are often formed by adding an "s" or "es" to the singular form (e.g., "cat" becomes "cats," and "box" becomes "boxes"). Other languages may have different rules for creating plurals.