Imber fossam aqua implet.

The subject is imber.

You can tell because:

• imber is in the nominative singular, the case normally used for the subject.
• implet means he/she/it fills or fills, so it needs a singular subject.
• The other nouns have different endings:
  • fossam is accusative singular, so it is the direct object.
  • aqua is ablative singular, so it is not the subject.

So the sentence structure is basically:

• imber = the thing doing the action
• fossam = the thing being filled
• aqua = what it is filled with

Because fossam is the accusative singular form of fossa, a first-declension noun.

The accusative case is commonly used for the direct object, the person or thing directly affected by the verb. In this sentence, the ditch is what gets filled, so fossam is in the accusative.

So:

• fossa = a ditch, trench
• fossam = a ditch / the ditch, as the direct object

Here aqua is in the ablative singular: aquā.

It means with water, not water as a direct object.

With implere (to fill), Latin often puts the material or substance used to fill something in the ablative. So:

• fossam = the ditch
• aquā = with water

In other words, Latin is treating water as the means or content by which the ditch is filled.

Because Latin has no articles like English the or a/an.

So a word like imber can mean:

• rain
• the rain
• sometimes a rainstorm

And fossam can mean:

• a ditch
• the ditch

The exact choice in English depends on context and on what sounds most natural in translation.

Implet is:

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

It comes from impleō, implēre, meaning to fill up or to fill.

So implet means fills or is filling, depending on context.

Because it is 3rd person singular, it matches the singular subject imber.

Latin word order is much more flexible than English word order because Latin uses case endings to show each word’s job in the sentence.

English depends heavily on order:

• Rain fills the ditch with water

Latin can move the words around more freely because the endings already show the roles:

• imber = subject
• fossam = direct object
• aquā = ablative

So Imber fossam aqua implet is natural Latin, especially with the verb at the end, which is very common.

Yes, often they could.

For example, these would still basically mean the same thing:

• Imber fossam aquā implet
• Imber aquā fossam implet
• Fossam imber aquā implet
• Aquā fossam imber implet

The case endings keep the grammar clear.

However, changing the order can change the emphasis. Latin writers often move words around to highlight what they want the reader to notice first or last.

Imber is a third-declension masculine noun.

Its dictionary form is:

• imber, imbris = rain, rainstorm

A learner might hesitate because the ending -er does not automatically tell you its declension the way first-declension -a often does. So it helps to learn it with its genitive:

• imber = nominative singular
• imbris = genitive singular

That tells you it belongs to the third declension.

Yes.

For a first-declension noun like aqua, the forms are:

• nominative singular: aqua
• ablative singular: aquā

In writing without macrons, both look the same: aqua.

With macrons, they are different:

• aqua = nominative
• aquā = ablative

In this sentence, the grammar shows that it must be ablative, because it means with water.

A useful way to see it is:

Subject + direct object + ablative of means/content + verb

So here:

• Imber = subject
• fossam = direct object
• aquā = what the ditch is filled with
• implet = verb

That gives the sense:

Rain fills the ditch with water.

This is a good example of how Latin uses cases, rather than English-style word order, to show the relationship between words.