In AP Latin, case is the form of a noun, pronoun, or adjective (nominative, genitive, dative, accusative, ablative, or vocative) whose ending signals the word's grammatical function in the sentence, such as subject, possessor, indirect object, direct object, or object of a preposition.
Case is how Latin tells you what a noun is doing in a sentence. English mostly uses word order ("the dog bites the man" vs. "the man bites the dog"), but Latin uses endings instead. Puella (nominative) is the subject; puellam (accusative) is the direct object; puellae could be genitive ("of the girl") or dative ("to/for the girl") depending on context. The six cases you need are nominative, genitive, dative, accusative, ablative, and vocative.
The CED puts it plainly in the essential knowledge for learning objectives 1.1.C, 1.2.C, and 1.3.C: Latin nouns have case, number, and gender, and "the case of a noun shows its function in a sentence." That one sentence is basically the whole game. Because Latin poets like Catullus scramble word order for meter and emphasis, case endings are often your only reliable map of who is doing what to whom. If you read a Catullus line left to right expecting English word order, you'll get lost. If you read the endings, the sentence unlocks.
Case sits under every "describe how grammar contributes to meaning" learning objective in the course, including AP Latin 1.1.C, 1.2.C, and 1.3.C in Unit 1 (Catullus's love poems, social and personal poems, and Catullus 64). Those LOs ask you to explain how grammar creates meaning in context, and for nouns, that means identifying case and naming its function. This skill never goes away. The literal translation questions and short-answer grammar questions on the exam (like the Caesar passages on the 2018 and 2019 Short Answer questions) all depend on reading endings correctly. Mistranslate a case and you've changed who owns what, who receives what, or who the subject even is. In Catullus especially, where hyperbaton flings adjectives far from their nouns, case (plus number and gender) is how you match them back up.
Keep studying AP Latin Unit SL2Apodi9BqlvQoqDkdk
Accusative (Unit 1)
The accusative is the single most-tested case function. It marks the direct object, but it also shows up as the subject of an infinitive in indirect statement, which is a classic AP grammar question. Knowing 'case' in general means nothing until you can name jobs like this one.
Ablative Absolute (Unit 1)
The ablative absolute is what happens when a case stops marking a single word's function and starts building an entire clause. A noun and participle both in the ablative create a standalone phrase ("with the city having been captured"). It's the best proof that case is structural, not just decorative.
Relative Clauses (Unit 1)
A relative pronoun takes its gender and number from its antecedent but its case from its job inside its own clause. That's why Catullus's sparrow poems can chain 'quicum,' 'quem,' and 'cui' for the same bird. Same antecedent, three different functions, three different cases.
Gerund (Unit 1)
The gerund is a verbal noun that declines through the oblique cases (genitive, dative, accusative, ablative), so translating one correctly means recognizing its case first. It's a reminder that case applies to anything noun-like, not just regular nouns.
Case questions show up everywhere. Multiple-choice stems ask things like "The word 'cui' in line 1 functions as what type of pronoun in this context?" or "What case is 'cui' in line 3, and what is its grammatical function?" Notice the pattern. You're never asked just to name the case; you're asked to name the case and its function (dative as indirect object, ablative of means, genitive of possession). Short-answer grammar questions on prose passages, like the released Caesar questions from 2018 and 2019, work the same way. On the translation FRQ (15% of your score), case errors are scored as errors. If you render an ablative as a direct object, you lose the segment. The practice move is simple. Every time you meet a noun or pronoun, say its case and its job out loud before you translate.
Declension and case sound interchangeable but aren't. A declension is the family a noun belongs to (1st through 5th), which determines what its endings look like. Case is the specific form within that family, which determines what the noun does in the sentence. So puella is a 1st-declension noun (its family), and puellam is its accusative case (its job as direct object). The exam tests case, not declension trivia. Nobody asks "what declension is this?" but they constantly ask "what case is this and why?"
Case is the noun ending that shows a word's function in the sentence, which is exactly how the CED phrases it for learning objectives 1.1.C, 1.2.C, and 1.3.C.
The six Latin cases are nominative (subject), genitive (possession), dative (indirect object), accusative (direct object), ablative (means, manner, and prepositional phrases), and vocative (direct address).
Latin word order is flexible, so in poetry like Catullus, case endings are your only reliable guide to who does what to whom.
Exam questions almost always pair case with function, so practice answering "dative, indirect object" rather than just "dative."
A relative pronoun gets its case from its role inside its own clause, not from its antecedent, which is why 'quem' and 'cui' can refer to the same noun.
On the translation FRQ, mistranslating a case counts as a scoring error, so checking endings before translating protects real points.
Case is the form of a Latin noun, pronoun, or adjective whose ending shows its grammatical function. The six cases are nominative, genitive, dative, accusative, ablative, and vocative, and the AP CED's essential knowledge states directly that "the case of a noun shows its function in a sentence."
No. Declension is the noun's family (1st through 5th), which determines its ending patterns. Case is the specific form within that pattern, which determines the noun's job. The exam asks about case and function, not which declension a word belongs to.
Yes, there's no way around it. Every translation segment and most grammar questions depend on recognizing endings instantly. The good news is the exam tests recognition in real passages from Vergil and Caesar, not isolated chart-filling.
Because a relative pronoun takes its case from its function inside its own clause, not from its antecedent. In Catullus's sparrow poems, 'quicum,' 'quem,' and 'cui' all refer to the same sparrow but serve different jobs in their clauses, which is exactly what exam questions about those lines test.
Use context, which is the skill behind learning objectives 1.1.B through 1.3.B. An ending like -ae could be genitive singular, dative singular, or nominative plural, so check the verb, nearby prepositions, and what function the sentence still needs to decide which reading works.