Equus etiam agricolae utilis est in agris.

The subject is equus.

• equus is nominative singular
• it means horse
• the nominative case is commonly used for the subject of the sentence

So equus ... est means the horse ... is.

Est is singular because it agrees with the subject, equus, which is singular.

• equus = the horse
• est = is

Even though agricolae might look plural at first, it is not the subject here.

Here agricolae is dative singular, meaning to/for the farmer.

This is because utilis often takes a dative with the person or thing that benefits from something.

So:

• equus agricolae utilis est = the horse is useful to the farmer

A native English speaker may expect something more like useful for the farmer, but Latin commonly uses the dative here.

Yes, by form alone agricolae can be several things:

• genitive singular = of the farmer
• dative singular = to/for the farmer
• nominative plural = farmers

But in this sentence, the grammar points to dative singular because it goes naturally with utilis est = is useful to/for.

Because utilis agrees with equus, which is masculine singular nominative.

Utilis is a third-declension adjective:

• masculine/feminine nominative singular: utilis
• neuter nominative singular: utile

Since equus is masculine, Latin uses utilis.

Utilis is a predicate adjective, and est is a linking verb.

So the sentence structure is:

• equus = subject
• utilis = adjective describing the subject
• est = is

Together, utilis est means is useful.

Etiam usually means also, even, or sometimes still, depending on context.

Here it most naturally means also:

• Equus etiam agricolae utilis est = The horse is also useful to the farmer

Its exact emphasis depends on context. It may suggest something like:

• the horse is useful too
• the horse is also useful, in addition to something else already mentioned

Because in takes the ablative when it means in or on a place where something is located.

• in + ablative = in/on somewhere
• in + accusative = into/onto somewhere

So:

• in agris = in the fields

If there were motion into the fields, Latin would use the accusative instead.

Agris is the ablative plural of ager, meaning field.

Latin often uses the plural where English also does:

• in agris = in the fields

This can refer to farmland in general, not necessarily a specific number of separate fields.

Latin word order is much more flexible than English word order because Latin uses word endings to show grammatical function.

English depends heavily on position:

• The horse is useful to the farmer in the fields

Latin can move parts around more freely:

• Equus etiam agricolae utilis est in agris
• Equus agricolae in agris utilis est
• Agricolae equus in agris utilis est

These do not all have exactly the same emphasis, but they can express the same basic idea.

In this sentence, the endings tell you the roles:

• equus = subject
• agricolae = dative
• agris = ablative after in

Latin has no articles.

That means Latin does not have separate words for:

• the
• a
• an

So equus can mean:

• a horse
• the horse

And agricolae can mean:

• to a farmer
• to the farmer

The exact choice in English depends on context.

Agricola is masculine, even though it belongs to the first declension, which often contains feminine nouns.

This is something English speakers often notice because the ending -a may look feminine.

So:

• agricola = farmer
• declension: first declension
• gender: masculine

Latin has some masculine first-declension nouns, especially words referring to male occupations or roles.

Here is a compact breakdown:

• equus — nominative singular, masculine; horse; subject
• etiam — adverb; also/even
• agricolae — dative singular; to/for the farmer
• utilis — nominative singular masculine adjective; useful
• est — 3rd person singular of esse; is
• in agris — prepositional phrase with in + ablative plural; in the fields

So the structure is essentially:

Horse + also + to the farmer + useful + is + in the fields.