Quotiens tonitrum auditur, canis retro ianuam latet.

Here quotiens introduces a subordinate clause and means whenever.

It is an adverb, and in this sentence it works like a conjunction in English: Whenever thunder is heard...

A learner will also see quotiens in direct or indirect questions, where it can mean how often? So its exact English translation depends on context:

• Quotiens venit? = How often does he come?
• Quotiens tonitrum auditur... = Whenever thunder is heard...

Auditur is the 3rd person singular present passive of audio, audire.

So literally it means is heard.

In Latin, this is a perfectly normal way to say that a sound is heard, especially when the focus is on the sound itself rather than on the person hearing it. English often prefers an active idea such as when one hears thunder or when thunder is heard, but Latin is happy with the passive form.

Compare:

• Puer tonitrum audit = The boy hears thunder
• Tonitrum auditur = Thunder is heard

In the passive version, the thing being heard becomes the grammatical subject.

Tonitrum is nominative singular here.

That may surprise English speakers, because in an active sentence thunder would be the direct object:

• aliquis tonitrum audit = someone hears thunder

But in this sentence the verb is passive:

• tonitrum auditur = thunder is heard

In a passive construction, the direct object of the active sentence becomes the subject of the passive sentence, so it appears in the nominative.

Also, tonitrum is a neuter second-declension noun, and its nominative singular ends in -um.

Canis is nominative singular, because it is the subject of latet.

The basic dictionary form is canis, canis for both masculine and feminine in the singular, though the gender depends on the individual dog or on usage in context. In many beginner sentences, it is simply treated as the dog.

So:

• canis latet = the dog hides / lies hidden

A common beginner point: canis is a 3rd-declension noun, so it does not look like a 1st- or 2nd-declension nominative.

Because lateo, latere means to lie hidden, to remain concealed, or to hide oneself in an intransitive sense.

So latet is active in form, but its meaning already includes the idea of being hidden. Latin does not need a passive here.

That is why:

• canis latet = the dog is hiding / lies hidden

This is different from a verb like celo:

• canem celo = I hide the dog
• canis celatur = the dog is hidden

But lateo does not normally mean hide something; it means be hidden or stay out of sight.

This is a very common question.

Here retro is being used as a preposition meaning behind, and it takes the accusative: retro ianuam = behind the door.

English speakers often expect Latin location words to use the ablative when there is no motion, but not every Latin preposition follows that pattern. Some prepositions simply govern a fixed case because that is how they work, and retro commonly takes the accusative.

So in this sentence:

• retro ianuam = behind the door

Even though latet describes position rather than movement, the accusative is still correct because it is required by retro.

Yes. Retro can be either:

1. an adverb: back, backward, behind
2. a preposition with the accusative: behind

In this sentence, because it is followed by ianuam, it is functioning as a preposition:

• retro ianuam

If it stood alone, it could be adverbial:

• canis retro latet would suggest something like the dog hides in the back / back there

So the presence of ianuam shows that retro is governing a noun here.

The present tense is used here for a general repeated action or habitual situation.

The sentence is not describing one single event only. It is saying what typically happens:

• whenever thunder is heard, the dog hides behind the door.

Latin often uses the present tense for this kind of regular or repeated truth, just as English can:

• When it rains, he stays inside
• Whenever thunder is heard, the dog hides...

So the present tense here does not mean only right now; it can also mean as a general pattern.

Latin word order is flexible, so putting Quotiens tonitrum auditur first is a natural way to set up the condition or time frame before the main statement.

English often does the same:

• Whenever thunder is heard, the dog hides behind the door.

The main clause is:

• canis retro ianuam latet

The subordinate clause comes first to establish when the main action happens.

Latin could rearrange the sentence in other ways for emphasis, but this order is clear and very natural.

No, not in the way English word order is fixed.

Latin uses endings, not just position, to show each word’s function. So the basic meaning would still be understood in several orders, for example:

• canis retro ianuam latet
• retro ianuam canis latet
• latet canis retro ianuam

That said, different orders can create different emphasis or style. In the given sentence, the verb latet comes at the end, which is a very common and natural Latin pattern.

So the order here is normal, but not the only possible one.

Because Classical Latin does not have definite and indefinite articles like English the and a/an.

So:

• canis can mean a dog or the dog
• ianuam can mean a door or the door
• tonitrum can mean thunder or the thunder, depending on context

The context tells you which English article makes the best sense.

This is something English speakers need to get used to: Latin often leaves article-like meanings unstated, and the translator supplies them naturally in English.