Post cenam serva omnia de mensa tollit.

Because post is a preposition that takes the accusative case when it means after.

• cena = dinner, meal
• cenam = dinner in the accusative singular

So:

• post cenam = after dinner

This is something you just learn with the preposition: post + accusative.

Yes. Serva is the subject.

It is the nominative singular form of serva, meaning female slave or maidservant. Since the verb tollit is third person singular, the subject must be singular too, and serva fits perfectly.

So the basic structure is:

• serva = the female slave / maidservant
• tollit = removes / lifts / takes away

Latin does not have definite or indefinite articles.

So serva can mean:

• a female slave
• the female slave

Which one is best depends on context. English has to choose, but Latin does not.

Omnia means all things or more naturally in English, everything.

It comes from omnis, omne = all, every. Here it is the neuter plural accusative form.

So although English often translates it as the singular-looking word everything, Latin expresses the idea as all things:

• omnia = all things / everything

Because Latin and English package this idea differently.

Latin uses:

• omnia = all things = plural

English often prefers:

• everything = grammatically singular

So this is a translation difference, not a grammar mistake. In Latin, omnia is naturally plural.

Because omnia is the direct object, not the subject.

The subject is serva, which is singular. Latin verbs agree with the subject, not with the object.

So:

• serva = subject, singular
• tollit = singular verb
• omnia = object, plural

That is why tollit is correct, not tollunt.

Tollit is:

• present tense
• third person singular
• from tollo, tollere

Here it means something like:

• removes
• takes away
• lifts off

So serva ... tollit = the maid removes ...

Because de is a preposition meaning from, down from, or off and it takes the ablative case.

• mensa = table
• de mensa = from the table / off the table

So the phrase tells you where the things are being removed from.

It is ablative singular.

You can tell because de requires the ablative. The dictionary form is mensa, but in the first declension the ablative singular also happens to be mensa.

So here:

• nominative singular: mensa = table
• ablative singular: mensa = from/on/with the table, depending on the preposition or context

In this sentence, because of de, it is definitely ablative.

Latin word order is more flexible than English word order because the endings show each word’s role in the sentence.

English depends heavily on position:

• The maid removes everything from the table.

Latin can move parts around more freely:

• Post cenam serva omnia de mensa tollit
• Serva post cenam omnia de mensa tollit
• Serva omnia de mensa post cenam tollit

All of these can make sense, though some orders may sound more natural or emphasize different parts.

In your sentence, post cenam comes first to set the scene: after dinner.

Yes. Latin often places time expressions in different positions.

For example, these are all possible in principle:

• Post cenam serva omnia de mensa tollit
• Serva post cenam omnia de mensa tollit
• Serva omnia de mensa post cenam tollit

Putting post cenam first gives it a slight emphasis as the time setting: After dinner, ...

Yes, it is a very natural combination.

• tollere can mean to lift, take away, remove
• de with the ablative often means down from or off

So de mensa tollit very naturally means:

• takes off the table
• removes from the table

A beginner might wonder that, but here it is clearly a noun.

There is also a verb servo meaning I save / preserve / keep, and an imperative serva! meaning save! or keep! But in this sentence, serva works as a noun because:

• it matches the singular verb tollit as a subject
• the whole sentence needs a subject
• the meaning fits naturally: the maid removes everything from the table

So here serva is definitely female slave / maidservant, not a verb.