Post meridiem auriga currum ante ianuam relinquit.

Literally, post meridiem means after midday/noon.

• post = after
• meridies = midday, noon
• meridiem is the accusative singular form of meridies

That form appears because post is a preposition that takes the accusative in Latin.

As a whole, post meridiem is a standard expression meaning in the afternoon or after noon. It is also the source of English p.m.

Because not all Latin nouns ending in -a are feminine.

auriga is a first-declension masculine noun. That is very common for certain nouns referring to male professions or roles, such as:

• nauta = sailor
• agricola = farmer
• poeta = poet
• auriga = charioteer/driver

So the ending -a tells you its declension, not necessarily its gender.

We know auriga is the subject because it is in the nominative singular form, and it matches the verb relinquit, which is third person singular: he/she leaves.

So:

• auriga = the driver/charioteer as subject
• relinquit = leaves

Latin often does not need a separate subject pronoun like he because the verb ending already shows the person and number.

currum is the direct object because it is in the accusative singular and it is the thing being left.

So in the sentence:

• auriga = the one doing the action
• relinquit = leaves
• currum = the thing left

A useful detail is that currus is a fourth-declension noun, so its accusative singular is currum.

Because ante is a preposition that regularly takes the accusative.

So:

• ante ianuam = before / in front of the door

This does not mean motion here. English speakers often expect accusative to imply movement, but with many Latin prepositions, the case is simply required by the preposition itself.

So ianuam is accusative because ante governs the accusative.

relinquit is the third person singular present active indicative of relinquere.

So it means:

• he/she leaves
• more literally, he/she leaves behind

In other contexts, relinquere can also mean abandon, leave behind, or quit, but here it simply means that the driver leaves the cart/chariot in a certain place.

Because Classical Latin has no articles.

So Latin does not normally have separate words for:

• the
• a/an

Whether you translate a noun as a driver, the driver, a door, or the door depends on the context.

That means:

• auriga could be a driver or the driver
• currum could be a chariot/cart or the chariot/cart
• ianuam could be a door/gate or the door/gate

Latin word order is much more flexible than English word order because Latin uses case endings to show grammatical function.

In English, word order does a lot of the work:

• The driver leaves the cart is different from
• The cart leaves the driver

But in Latin, endings already show who is doing what.

So Post meridiem auriga currum ante ianuam relinquit can be arranged this way for style or emphasis:

• Post meridiem comes first to set the time
• relinquit comes at the end, which is very common in Latin

A different order could still mean basically the same thing, as long as the forms stay the same.

Because the ending of the verb already tells you the subject is third person singular.

In relinquit, the -t ending means:

• he leaves
• she leaves
• it leaves

Since the noun auriga is already present, Latin does not need to add a pronoun.

If a pronoun were added, it would usually be for emphasis, not because grammar requires it.

It can mean either, depending on context.

ianua often means:

• door
• front door
• entrance
• sometimes gate

So ante ianuam could mean in front of the door or before the entrance/gate, depending on what kind of building or setting is being described.

It is a prepositional phrase being used adverbially.

That means it tells you when the action happens:

• Post meridiem = in the afternoon / after noon

So grammatically it is still a phrase with a preposition (post) and its object (meridiem), but in the sentence it functions like an adverb of time.