Impressio signum habet.

The subject is impressio, and the object is signum.

A quick way to see that:

• impressio is a nominative singular form, so it works as the subject.
• signum is a neuter noun, and in neuter nouns the nominative and accusative singular are the same. Here it is being used as the accusative singular, so it is the direct object.
• habet means has, so the sentence structure is:

Impressio = the subject
signum = the thing being had
habet = has

So the basic pattern is subject + object + verb.

Because habet means he/she/it has, while habeo means I have.

The subject here is impressio, which is a third-person singular noun, so the verb must also be third-person singular:

• habeo = I have
• habes = you have
• habet = he/she/it has

Since impressio is it, Latin uses habet.

Habet is the present active indicative, third person singular, of habere.

So:

• dictionary form: habere = to have
• sentence form: habet = has

This tells you the action is:

• present: happening now
• active: the subject is doing the action
• indicative: a simple statement of fact
• third person singular: he/she/it

Because Latin normally does not have articles like English a, an, or the.

So Impressio signum habet could be understood in English as:

• The impression has a sign
• The impression has the sign
• sometimes just An impression has a sign

Which one is best depends on the context. Latin leaves that unstated unless something else in the sentence makes it clear.

Because signum is a second-declension neuter noun.

For this kind of noun:

• nominative singular often ends in -um
• accusative singular also ends in -um

That is why signum can look the same whether it is the subject or the object. In this sentence, it is the object.

Its basic dictionary form is:

• signum, signi = sign, mark, symbol, seal, standard, etc.

No. Here impressio is nominative singular, not ablative.

It belongs to the third declension, and nouns of this type often have a nominative singular ending in -io.

Its dictionary entry would be something like:

• impressio, impressionis

That means:

• nominative singular: impressio
• genitive singular: impressionis

So even though an English speaker may associate final -o with another case, in this word the full ending is -io, and the form here is simply the normal nominative singular.

Because impressio is not in the accusative.

If signum were the subject and impressio were the object, you would expect the object form of impressio, which would be impressionem.

So compare:

• Impressio signum habet = The impression has a sign
• Signum impressionem habet = The sign has an impression

That is a very important Latin skill: use the case endings, not just the English word order, to see who is doing what.

No. Latin word order is much more flexible than English word order.

This sentence uses a very common Latin arrangement:

• subject + object + verb

So Impressio signum habet is perfectly normal.

But Latin could also say, for example:

• Signum impressio habet
• Impressio habet signum

Those would still mean basically the same thing, though the emphasis may shift slightly.

In Latin, the endings usually matter more than the position.

They are from two different declensions:

• impressio, impressionis: third declension
• signum, signi: second declension neuter

That matters because different declensions use different endings for case and number.

In this sentence:

• impressio = nominative singular
• signum = accusative singular

Learning the declension of each noun helps you recognize its role in the sentence.

Yes, very much so.

A native English speaker may notice:

• impressio is clearly related to impression
• signum is related to words like sign and signal
• habere is related more indirectly to words formed from Latin roots meaning have, hold, or possess

These connections can help you remember vocabulary, but you should still be careful: a Latin word does not always match the English word in every detail or shade of meaning.

In a basic Classical pronunciation, you could say it roughly like:

im-PRESS-ee-o SEENG-num HAH-bet

A few helpful points:

• impressio has a clear -si-o at the end
• signum has gn, which in Classical Latin is pronounced together, roughly like ngn
• habet has a clear h in Classical pronunciation

If you are learning Ecclesiastical pronunciation, some sounds may differ slightly, especially around ti, ci, and similar combinations, but this sentence is still fairly straightforward to say.