---
title: "Imperator — AP Latin Definition & Translation Guide"
description: "Imperator means \"commander\" or \"general\" in Latin, a 3rd-declension noun from imperare. Learn how to translate it in context and how it differs from imperium."
canonical: "https://fiveable.me/ap-latin/key-terms/imperator"
type: "key-term"
subject: "AP Latin"
unit: "Unit 1"
---

# Imperator — AP Latin Definition & Translation Guide

## Definition

Imperator (3rd declension masculine, gen. imperatoris) means "commander" or "general" in AP Latin. Built from imperare ("to command"), it names the person holding military authority. Later it became the title that gives us "emperor," but in Caesar and Vergil's world it usually just means the general in charge.

## What It Is

**Imperator** is a third-declension masculine [noun](/ap-latin/unit-3 "fv-autolink") (imperator, imperatoris) meaning "commander" or "general." It comes straight from the verb *imperare*, "to command, to order," plus the agent suffix *-tor*, which turns a verb into "the person who does it." So an imperator is literally "the one who gives the commands." That word-formation pattern is exactly the kind of skill the CED expects you to use ([AP Latin](/ap-latin "fv-autolink") 1.21.B), and it works for a whole family of words: *victor* from *vincere*, *amator* from *amare*, *imperator* from *imperare*.

In Republican-era Latin (the world of [Caesar](/ap-latin/key-terms/caesar "fv-autolink")'s prose and the legendary past Vergil writes about), imperator is a military title, not a royal one. Soldiers could acclaim a victorious general as imperator after a big win. Only later did it harden into the imperial title behind the English word "emperor." When you hit imperator in an AP passage, translate it as "general" or "commander" unless the context clearly points to the emperor. Watch the case ending too: *imperator* is the subject, *imperatorem* is the direct object, *imperatori* means "to/for the commander," and *imperatoris* means "of the commander" (AP Latin 1.21.C).

## Why It Matters

Imperator shows up in [Unit 1](/ap-latin/unit-1 "fv-autolink")'s prose practice and connects to Topic 1.21 (the Vergil Aeneid Trojan War study guide), where war leadership is the whole story. The CED's vocabulary objectives are the core here. AP Latin 1.21.A says you have to know the required vocabulary list cold, and 1.21.B says you should crack unfamiliar words using roots and word formation. Imperator is a model [case](/ap-latin/key-terms/case "fv-autolink") for both. If you know *imperare*, you can decode imperator, imperium, and even English derivatives like "imperative" and "imperial." On top of that, 1.21.C asks you to explain how grammar shapes meaning, and imperator's case endings tell you whether the commander is acting, being acted on, or possessing something. Getting the case right is the difference between "the general saw the Trojans" and "the Trojans saw the general."

## Connections

### [Imperium (Unit 1)](/ap-latin/key-terms/imperium)

[Imperium](/ap-latin/key-terms/imperium "fv-autolink") is the abstract noun from the same root, meaning the power to command itself. Think of it this way. The imperator is the person, and imperium is the authority he wields. They share the root *imperare*, so spotting one helps you decode the other on sight.

### [Aquila (Unit 1)](/ap-latin/key-terms/aquila)

The [aquila](/ap-latin/key-terms/aquila "fv-autolink") (eagle standard) was the symbol a Roman legion carried into battle under its imperator. In military prose, the commander and the eagle travel together. Seeing one word primes you to expect the other in battle narratives.

### Trojan War (Topic 1.21, Unit 1)

Vergil's Trojan War [narrative](/ap-latin/unit-4 "fv-autolink") is full of leaders commanding armies, so command vocabulary like imperator and imperium frames how you read figures like Agamemnon and Aeneas. The Aeneid filters Greek legend through a very Roman idea of military leadership.

### Trojan Horse (Topic 1.21, Unit 1)

The Trojan Horse episode in Aeneid Book 2 is a story about command decisions gone wrong. Troy's leaders order the horse brought inside the walls. Reading that passage means tracking who is giving orders, which is exactly the territory of *imperare* and its derivatives.

## On the AP Exam

Imperator is most likely to appear inside a Latin prose passage where you have to translate it accurately and account for its case. On the multiple-choice section, a stem might ask what *imperatorem* refers to in a line, or test whether you can tell a genitive (*imperatoris*) from a dative (*imperatori*). On translation FRQs, the graders score literal accuracy, so "commander" or "general" earns the point while a vague "leader" or an anachronistic "emperor" can cost you in Republican-era contexts. No released FRQ in recent years has hinged on this exact word, but it belongs to the required-vocabulary skill set tested constantly under AP Latin 1.21.A. The smartest prep move is learning the *-tor* agent-noun pattern, because it unlocks dozens of words beyond this one.

## imperator vs imperium

Imperator is the person; imperium is the power. An imperator is a flesh-and-blood commander, while imperium is the abstract authority to command (and later, the empire that authority built). Same root, different jobs in a sentence. If you translate *imperium* as "general" or *imperator* as "empire," you lose the translation point. A quick check helps. Agent nouns in *-tor* are always people, while *-ium* nouns are usually abstract things.

## Key Takeaways

- Imperator is a third-declension masculine noun meaning "commander" or "general," formed from the verb imperare ("to command") plus the agent suffix -tor.
- In the prose and poetry on the AP Latin syllabus, imperator usually means a military general, not an emperor, so match your translation to the era of the passage.
- Imperator is the person who commands, while imperium is the abstract power to command; mixing them up is a classic translation error.
- The case ending tells you the commander's role in the sentence: imperator (subject), imperatorem (object), imperatori (indirect object), imperatoris (possessive).
- Knowing the -tor agent-noun pattern lets you decode unfamiliar words on the exam, exactly the word-formation skill AP Latin 1.21.B rewards.

## FAQs

### What does imperator mean in AP Latin?

Imperator means "commander" or "general." It's a third-declension masculine noun (genitive imperatoris) built from the verb imperare, "to command."

### Does imperator mean emperor?

Not usually in AP Latin passages. In Republican-era Latin it means a military general, often one acclaimed by his troops after a victory. The word only became the imperial title (and the root of English "emperor") under Augustus and later rulers, so translate based on the passage's context.

### What's the difference between imperator and imperium?

Imperator is the person holding command; imperium is the power of command itself. They share the root imperare, but one is a concrete agent noun (-tor = "the one who does it") and the other is abstract.

### How do I translate imperatorem versus imperatoris?

Imperatorem is accusative, so it's the direct object ("he saw the commander"). Imperatoris is genitive, meaning "of the commander" ("the commander's army"). AP Latin 1.21.C expects you to use case endings like these to nail the noun's function.

### Is imperator on the AP Latin vocabulary list?

Command vocabulary from the imperare family is core AP Latin material, and AP Latin 1.21.A requires you to know the required vocabulary list. Even if a specific form is unfamiliar, the -tor suffix and the root imperare let you decode it using word-formation patterns, which the CED explicitly tests.

## Related Study Guides

- [1.21 Vergil Aeneid Trojan War Study Guide](/ap-latin/unit-1/vergil-aeneid-trojan-war-study-guide/study-guide/b288d4e9c3fac2e7)

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