Pueri ante cenam manus lavare debent.

Pueri is the nominative plural of puer, meaning boy. So here it means boys and is the subject of the sentence.

• puer = boy
• pueri = boys

Because debent is they ought / they must, the subject has to be plural, so pueri fits perfectly.

Because ante as a preposition normally takes the accusative case when it means before in the sense of before a time/event.

So:

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

That is why Latin says ante cenam = before dinner.

Here manus is accusative plural, meaning hands.

It is the direct object of lavare:

• lavare = to wash
• manus lavare = to wash hands

A learner may find this confusing because manus belongs to the fourth declension, and some of its forms look the same. In careful spelling with macrons, the plural form would be manūs, but many beginner texts leave macrons out, so you just see manus.

Latin often leaves out possessive words like my, your, or their when the meaning is obvious from the context.

So manus lavare debent literally means they ought to wash hands, but in natural English we usually say they ought to wash their hands.

Latin does this especially with body parts when the possessor is clear.

Because debent is followed by an infinitive.

• debent = they ought / they must
• lavare = to wash

So the pattern is:

• debent lavare = they ought to wash / they must wash

This is similar to English:

• They ought to wash
• They must wash

The second verb stays in a basic form.

Debent can be translated in a few ways depending on context:

• must
• should
• ought to

Its basic idea is obligation or duty.

So this sentence could be understood as:

• The boys must wash their hands before dinner
• The boys should wash their hands before dinner
• The boys ought to wash their hands before dinner

If the context is a rule, must may fit best. If it is advice, should or ought to may sound better.

Debent is the third person plural present active indicative of debeo, debere.

Breaking it down:

• debeo = I owe / I ought / I must
• debent = they ought / they must

It matches the plural subject pueri.

Yes. Latin word order is much more flexible than English word order because the endings show how the words function.

This sentence is arranged in a very natural and clear way:

• Pueri = subject first
• ante cenam = time phrase
• manus lavare = action
• debent = main verb at the end

But other orders are possible, for example:

• Pueri manus ante cenam lavare debent
• Ante cenam pueri manus lavare debent

These all mean basically the same thing, though the emphasis may shift slightly.

Classical Latin has no definite article and no indefinite article.

So Latin does not have separate words for:

• the
• a
• an

That means:

• pueri can mean boys or the boys
• cenam can mean dinner or the dinner, depending on context

English requires an article more often, so translators have to add one where it sounds natural.

Not always, but in this sentence it is a preposition.

Here it is followed by a noun in the accusative:

• ante cenam = before dinner

In some contexts, ante can also act more like an adverb meaning beforehand or earlier, but that is not what is happening here.

Latin is being very literal here: manus means hands, plural.

Since people normally wash both hands, the plural is natural. English also usually uses the plural in this expression: wash your hands.

If Latin wanted to say wash the hand, it would use a singular form instead.

Manus is a fourth-declension noun. That matters because its endings are different from the much more common first- and second-declension nouns.

Its basic forms are:

• nominative singular: manus = hand
• accusative singular: manum
• nominative plural: manus or manūs
• accusative plural: manus or manūs

So beginners may expect something like a second-declension plural ending, but manus does not follow that pattern.

No, not in this sentence.

With expressions of time, ante means before in a temporal sense:

• ante cenam = before dinner

If you wanted to say in front of something physically, Latin would usually use a different expression, such as ante with a noun referring to an object or place where the context clearly shows physical position. Here, because cena is an event or meal, the meaning is clearly temporal.

Yes. Lavare manus is a normal way to say to wash one’s hands.

Latin often uses:

• verb + body part
• without an explicit possessive adjective

So manus lavare is exactly the kind of phrasing you should expect.

A very literal translation would be:

Boys before dinner hands to wash ought

That sounds unnatural in English, of course. A normal English translation would be:

The boys ought to wash their hands before dinner.

This is a good example of why Latin should not be translated simply by keeping the same word order as English.