Declension
A pattern of endings that a Latin noun (or adjective or pronoun) follows to show its case and number.
Latin has 5 declensions. Each declension has its own set of endings for the 6 cases Γ 2 numbers (singular and plural). Memorizing declension patterns is a large part of first-year Latin.
Example: First declension nouns (mostly feminine) end in -a in the nominative singular: puella, mensa, terra.
First Declension
Mostly feminine nouns ending in -a (nominative singular).
Pattern endings: -a, -ae, -ae, -am, -a, -ae, -arum, -is, -as, -is. Classic examples: puella (girl), mensa (table), aqua (water), terra (earth).
Second Declension
Mostly masculine nouns ending in -us (or -er), and neuter nouns ending in -um.
Masculine pattern: -us, -i, -o, -um, -o, -i, -orum, -is, -os, -is. Examples: servus (slave), puer (boy), bellum (war), verbum (word).
Third Declension
The largest declension, with nouns of all three genders and varied nominative endings.
Third declension is harder because you can't predict the nominative from the stem β you have to memorize both forms together. Rex, regis. Civis, civis. Nomen, nominis. Henle Latin spends significant time here.
Fourth Declension
Mostly masculine nouns ending in -us, with genitive in -us (long u).
Smaller declension. Examples: manus (hand, feminine), domus (home, feminine), exercitus (army, masculine).
Fifth Declension
Mostly feminine nouns ending in -es.
Smallest declension. Key examples: res (thing, affair β the root of English 'real'), dies (day β one of the few masculine fifth-declension nouns).
Nominative Case
The case of the subject of the sentence.
The nominative is the 'naming' case. The subject of the verb goes in the nominative. It's also the form you look up in a Latin dictionary.
Example: PUELLA cantat β THE GIRL is singing.
Genitive Case
Shows possession or a noun acting on another noun.
The genitive is the 'of' case. It's how you say 'of the girl' or 'the girl's book'. In Latin dictionaries, nouns are listed with their nominative and genitive forms because the genitive tells you which declension the noun belongs to.
Example: liber PUELLAE β the girl'S book, or the book OF THE girl.
Dative Case
The case of the indirect object β the person or thing receiving the action.
The dative is the 'to/for' case. It's used for indirect objects and also with certain verbs that take a dative object (like to please someone, to help someone).
Example: librum PUELLAE do β I give the book TO THE GIRL.
Accusative Case
The case of the direct object.
The accusative marks the direct object β the thing that receives the action of the verb. It's also used after many prepositions (ad, in, contra, per, trans).
Example: puella LIBRUM legit β the girl reads THE BOOK.
Ablative Case
A 'by/with/from' case showing means, manner, separation, or place from which.
The ablative is Latin's catch-all adverbial case. It's used for means ('with a sword'), manner ('with joy'), agent after passive verbs ('by the enemy'), and many specific idioms. Memorizing ablative uses is a multi-year project.
Example: GLADIO pugnat β he fights WITH A SWORD.
Vocative Case
The case of direct address.
The vocative is used when you're calling or addressing someone. For most declensions, the vocative looks identical to the nominative. The one major exception is second-declension masculine nouns in -us, which have a vocative in -e.
Example: 'Et tu, BRUTE?' β 'You too, BRUTUS?' (the famous vocative).