---
title: "Conjugation — AP Latin Definition & Exam Guide"
description: "Conjugation is the group a Latin verb belongs to, which dictates its endings. Knowing all four (plus irregulars like sum) is the backbone of AP translation."
canonical: "https://fiveable.me/ap-latin/key-terms/conjugation"
type: "key-term"
subject: "AP Latin"
---

# Conjugation — AP Latin Definition & Exam Guide

## Definition

In AP Latin, a conjugation is the group a verb belongs to (1st through 4th, plus 3rd -io), which dictates the specific endings that mark its person, number, tense, voice, and mood. Irregular verbs like sum, esse don't follow these expected patterns and have to be memorized separately.

## What It Is

A conjugation is a family of [verbs](/ap-latin/unit-4 "fv-autolink") that all form their endings the same way. Latin has four main conjugations (plus the 3rd -io hybrid), and you can tell which family a verb belongs to from its principal parts, especially the second one, the [infinitive](/ap-latin/key-terms/infinitive "fv-autolink") (amāre = 1st, monēre = 2nd, regere = 3rd, audīre = 4th). Once you know the conjugation, you know exactly which endings attach to the stem.

Why does this matter? Because in Latin, the verb's stem plus its ending tells you five things at once: [person](/ap-latin/key-terms/person "fv-autolink"), number, tense, voice, and mood. The conjugation is the rulebook that says which ending means what. The catch is that irregular verbs (the big one is *sum, esse*, 'to be') ignore the rulebook entirely. Worse, Vergil sometimes omits forms of *sum* completely, so you have to infer 'is' or 'was' from context. That move shows up constantly in the Aeneid passages you read for the exam.

## Why It Matters

Conjugation is flagged as 'repeated for review' essential knowledge under learning objective **[AP Latin](/ap-latin "fv-autolink") 4.3.D** (describe how Latin verbs and verbals function in context and contribute to the meaning of the text), which sits in Unit 4's required Aeneid Book 2 readings (lines 40-56 and 201-249, the Laocoön scenes). You can't do 4.3.D without conjugations, because identifying a verb's tense, voice, and mood starts with knowing which ending pattern it follows. It also feeds directly into translation work under **AP Latin 4.3.A** and **4.3.B** (defining words and identifying meaning in context). When Laocoön hurls his spear or the serpents attack, [Vergil](/ap-latin/unit-3 "fv-autolink")'s verb choices (vivid presents, perfects, subjunctives in conditions) carry the drama, and you only catch them if you can parse the forms.

## Connections

### [Infinitive (Unit 4)](/ap-latin/key-terms/infinitive)

The infinitive is your conjugation ID card. The second principal part's vowel before -re (ā, ē, e, ī) tells you instantly which conjugation a verb belongs to, which tells you every ending it will ever take.

### [Participle (Unit 4)](/ap-latin/key-terms/participle)

Participles are built from the same conjugation stems as finite verbs. A 3rd conjugation present [participle](/ap-latin/key-terms/participle "fv-autolink") (regens) and a 1st conjugation one (amans) follow the same logic, so conjugation knowledge transfers straight to verbals.

### [Imperative Mood (Unit 4)](/ap-latin/key-terms/imperative-mood)

Imperatives are formed by conjugation too, usually the present [stem](/ap-latin/key-terms/stem "fv-autolink") with or without -te. Knowing the conjugation lets you spot commands fast in speeches like Laocoön's warning to the Trojans.

### [Gerund (Unit 4)](/ap-latin/key-terms/gerund)

Gerunds (the -nd- [verbal](/ap-latin/unit-5 "fv-autolink") nouns) take their stem vowel from the verb's conjugation, like amandi vs. regendi. Same family rules, different part of speech.

## On the AP Exam

Conjugation rarely appears as a vocabulary word on the exam itself. Instead, it's the skill underneath almost everything. Multiple-choice questions ask you to identify a verb's tense, voice, or mood, which means recognizing endings by conjugation. The literal translation FRQ requires you to render every verb's person, number, tense, voice, and mood accurately, and graders dock you for translating a perfect as a present or an active as a passive. Watch for two traps in the required Aeneid passages: irregular verbs like sum, esse that don't follow any conjugation's pattern, and omitted forms of sum that you have to supply from context. If your translation is missing a verb, Vergil probably dropped an est on purpose.

## conjugation vs Declension

Both words mean 'a family of endings,' but conjugation is for verbs and declension is for nouns and adjectives. A verb's conjugation determines endings that show person, tense, voice, and mood; a noun's declension determines endings that show case and number. Easy memory hook: you conjugate verbs, you decline nouns.

## Key Takeaways

- A conjugation is the group a Latin verb belongs to, and that group dictates the specific endings the verb uses.
- A verb's stem plus its ending tells you its person, number, tense, voice, and mood, so parsing starts with knowing the conjugation.
- The infinitive (second principal part) is the fastest way to identify a verb's conjugation: -āre, -ēre, -ere, -īre.
- Irregular verbs like sum, esse do not follow the expected patterns of any conjugation and must be memorized on their own.
- Vergil sometimes omits forms of sum entirely, so you have to infer 'is' or 'was' from context when translating the Aeneid.
- On the literal translation FRQ, getting a verb's tense, voice, or mood wrong costs points, and all three depend on reading the conjugation's endings correctly.

## FAQs

### What is a conjugation in AP Latin?

A conjugation is a group of verbs that share the same set of endings. Latin has four main conjugations, and the conjugation determines how a verb shows person, number, tense, voice, and mood, per essential knowledge under AP Latin 4.3.D.

### What's the difference between conjugation and declension?

Conjugation applies to verbs; declension applies to nouns and adjectives. Conjugation endings encode tense, voice, mood, person, and number, while declension endings encode case and number.

### Do all Latin verbs follow a conjugation pattern?

No. Irregular verbs like sum, esse ('to be') don't follow the expected patterns of any conjugation. You have to memorize their forms separately, and Vergil sometimes leaves forms of sum out entirely so you must infer them from context.

### How do I tell which conjugation a verb belongs to?

Look at the second principal part, the present infinitive. The vowel before -re gives it away: -āre is 1st, -ēre is 2nd, -ere is 3rd, and -īre is 4th, with 3rd -io verbs as a hybrid of 3rd and 4th.

### Is conjugation actually tested on the AP Latin exam?

Not as a definition question, but it's tested constantly in practice. Multiple-choice items ask you to identify verb forms, and the literal translation FRQs require accurate tense, voice, and mood for every verb, all of which depend on conjugation.

## Related Study Guides

- [Multiple-Choice Questions (MCQ)](/ap-latin/ap-latin-exam/ap-latin-mcq/study-guide/ap-latin-mcq)

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