Latin nouns are distinguished by grammatical case, with a termination, or suffix, determining its use in the sentence: subject, predicate, etc. A case for a given word is formed by suffixing a case ending to a part of the word common to all its cases called a stem. Stems are classified by their last letters as vowel or consonant. Vowel stems are formed by adding a suffix to a shorter and more ancient segment called a root. Consonant stems are the root (roots end in consonants). The combination of the last letter of the stem and the case ending often results in an ending also called a case ending or termination. For example, the stem "puella-" receives a case ending "-m" to form the accusative case "puellam" in which the termination "-am" is evident.