This chapter discusses key grammatical properties of three major classes of nouns in English: common nouns, pronouns, and proper nouns. We demonstrate that the lexical properties of these nouns determine their external syntactic structures. We then examine three types of agreement relationships in English: noun-determiner, pronoun-antecedent, and subject-verb agreement. We observe that the agreement relationship between a noun and its determiner concerns number (NUM) features of the two, while that between a pronoun and its antecedent involves all the three morphosyntactic agreement (AGR) features: person (PER), number (NUM), and gender (GEND). For its part, the subject-verb agreement relationship depends not only on morphosyntactic agreement (AGR) features but also on the semantic index (IND) feature. This hybrid agreement framework offers us a streamlined analysis of mismatches that involve the respective NUM values of subject and verb. The analysis developed here is extended to partitive NPs in English.