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.
Imperator is a third-declension masculine noun (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 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'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).
Imperator shows up in Unit 1'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 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."
Keep studying AP Latin Unit 1
Imperium (Unit 1)
Imperium 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)
The aquila (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 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.
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 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.
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.
Imperator means "commander" or "general." It's a third-declension masculine noun (genitive imperatoris) built from the verb imperare, "to command."
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.
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.
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.
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.