Si quid in cista latet, mater eam aperit.

After words like si (if), Latin usually uses quis/quid instead of aliquis/aliquid.

So:

• si quid = if anything, if something
• not usually si aliquid

This is a very common pattern:

• si quis venit = if anyone comes
• si quid accidit = if anything happens

So quid here is an indefinite pronoun, not a question word.

No. Even though quid can mean what? in a direct question, that is not what it is doing here.

In this sentence, si tells you that quid is indefinite:

• si quid latet = if anything is hidden

So here quid means anything or something, not what?

Quid is neuter singular, and here it is the subject of latet.

So in the clause:

• si quid in cista latet

the thing that is hidden is quid = anything / something.

That is why latet is singular: its subject is singular.

Because in with the ablative usually means in or inside in the sense of location.

• in cista = in the box/chest
• in cistam would usually mean into the box/chest

So the sentence is describing where something is hidden, not movement into the box.

Latet is:

• 3rd person singular
• present tense
• active voice
• indicative mood

from the verb lateo, latere, meaning to lie hidden, to be hidden.

So quid latet means:

• something is hidden
• or more literally, something lies hidden

The subject of aperit is mater.

• mater = mother
• aperit = opens

So:

• mater eam aperit = mother opens it

Latin often puts the subject before the verb, but the verb ending also helps you identify it.

Eam refers to cista.

• cista is feminine singular
• eam is feminine singular accusative

So eam means it, specifically the box/chest, not the hidden thing.

That is important:

• quid = the hidden thing
• eam = the box that mother opens

It would only be neuter if it referred to quid. But it does not.

The sentence means:

• If anything is hidden in the box, mother opens the box.

Since cista is feminine, the pronoun referring to it must also be feminine:

• cista → eam

If Latin wanted to say that mother opens the hidden thing, then the pronoun would need to match that noun instead.

Yes, Latin word order is flexible.

This order is perfectly natural:

• Si quid in cista latet, mater eam aperit.

But Latin could rearrange the words for emphasis, for example:

• Si quid latet in cista, mater eam aperit.
• Mater, si quid in cista latet, eam aperit.
• Eam mater aperit, si quid in cista latet.

The endings show the grammar, so the meaning stays basically the same. The main difference is emphasis and style.

Latin often uses the present tense for a general situation, habitual action, or simple statement of fact.

So this sentence means something like:

• If anything is hidden in the box, mother opens it
• in the sense of a general rule or repeated behavior

It is not necessarily talking about one single event happening right now. It can describe what mother does whenever that situation occurs.

Yes, it is a simple if sentence with si and the indicative.

Both clauses use the present indicative:

• si quid in cista latet
• mater eam aperit

This often expresses a simple present condition:

• if X happens, Y happens

So it can be understood as a straightforward, factual, or habitual condition.

Eam is the feminine singular accusative form of is, ea, id, a very common demonstrative/pronominal word often translated as he, she, it, that, or simply the one depending on context.

Here it works like an object pronoun:

• aperit eam = opens it

Because it is accusative, we know it is the direct object of aperit.

Grammatically, Latin often omits pronouns when they are obvious, but here eam is helpful because it tells you clearly what mother opens.

• mater aperit by itself would just mean mother opens
• the listener would wonder: opens what?

So eam makes the sentence complete and clear by pointing back to cista.