In eo praedio pomarium magnum est, ubi mala et pira bene crescunt.

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

So:

• in eo praedio = in that estate / on that farm
• praedio is ablative singular
• eo is also ablative singular, agreeing with praedio

If Latin wanted to express motion into a place, in would usually take the accusative instead.

Here eo means that.

It comes from the demonstrative pronoun is, ea, id, and here it is being used like an adjective to modify praedio:

• eo praedio = that estate / that farm

A beginner might confuse it with the adverb eo meaning to that place, but that is not what is happening here. In this sentence, eo clearly agrees with praedio in case, number, and gender, so it is an adjective-like demonstrative.

Praedium usually means estate, property, or farm.

It refers to a piece of land or a rural property. In this sentence, it is the larger place in which the orchard is located.

So the idea is:

• praedium = the estate/farm/property
• pomarium = the orchard within it

Pomarium means orchard.

It is a neuter noun, and here it is the subject of est:

• pomarium magnum est = there is a large orchard / the orchard is large

It is related to pomum, a fruit word often associated with orchard produce such as apples.

Latin word order is much freer than English word order.

Both pomarium magnum est and magnum pomarium est would be understandable. The version in your sentence places the noun first and then the adjective:

• pomarium magnum est = there is a large orchard

This order can feel natural and straightforward in Latin. The meaning does not change much just because the adjective comes after the noun.

Because it agrees with pomarium.

• pomarium is neuter singular
• so magnum must also be neuter singular

This is standard Latin adjective agreement: adjectives agree with the nouns they describe in gender, number, and case.

Est means is and is the 3rd person singular of esse.

In this sentence it links the subject pomarium with the description magnum:

• pomarium magnum est = the orchard is large

In smoother English, the whole clause is often translated as There is a large orchard, but Latin is literally saying A large orchard is in that estate.

Here ubi means where.

It introduces a clause describing a place:

• ubi mala et pira bene crescunt = where apples and pears grow well

You can think of it as a relative adverb. In English, we might also say in which.

So this clause tells us something about the location of the orchard: it is a place where apples and pears grow well.

A learner could reasonably wonder about that.

Grammatically, ubi refers to a place, so it can connect naturally with the idea of either the estate or the orchard. Because pomarium is the closest place-word, many readers will take the clause as describing the orchard directly:

• a large orchard, where apples and pears grow well

But in practice the sense overlaps, since the orchard is inside the estate anyway. The important point is that ubi introduces a clause about the location.

Because they are plural nouns meaning apples and pears.

• mala is the neuter plural of malum
• pira is the neuter plural of pirum

So:

• mala et pira = apples and pears

A beginner may expect endings that look more like masculine or feminine plurals, but many fruit nouns are neuter, and neuter plural nominative nouns often end in -a.

Because its subject is plural:

• mala et pira = apples and pears

Since there are two coordinated subjects, Latin uses the plural verb:

• crescunt = grow

So:

• mala et pira bene crescunt = apples and pears grow well

Bene is an adverb meaning well.

It modifies crescunt:

• crescunt = grow
• bene crescunt = grow well

So it tells us how the apples and pears grow.

Because Classical Latin has no articles.

So:

• praedium can mean a farm, the farm, or just farm/estate depending on context
• pomarium can mean an orchard or the orchard
• mala et pira can mean apples and pears or the apples and pears

English must choose an article, but Latin usually leaves that to context.

Yes.

A helpful way to break it down is:

• In eo praedio = In that estate / On that farm
• pomarium magnum est = there is a large orchard
• ubi mala et pira bene crescunt = where apples and pears grow well

So Latin is using a very common pattern: a place phrase first, then a form of esse to state that something exists there.

Yes. A very literal translation would be:

In that estate a large orchard is, where apples and pears grow well.

That is not natural English, but it helps show the Latin structure more clearly. A smoother English version would be something like:

On that farm there is a large orchard where apples and pears grow well.

Both reflect the same Latin meaning.