The term 'Proper or Common Parts of Speech' refers to the eight categories of words used in the English language. These categories are nouns, verbs, adjectives, adverbs, pronouns, prepositions, conjunctions, and interjections. The crossword solution for the term 'Nouns' is five letters long and refers to a word that is used to name a person, place, thing, quality, or action. Nouns are one of the most important parts of speech and are used to provide structure and meaning to sentences.