Magistra usum huius vocabuli clare explicat.

Magistra is in the nominative singular, which is the case normally used for the subject in Latin. It means the female teacher or mistress/teacher.

The verb explicat is also third person singular, so it matches a singular subject like magistra: the teacher explains.

Usum is the direct object of explicat. In Latin, the direct object is usually put in the accusative case.

So the structure is:

• magistra = subject
• usum = direct object
• explicat = verb

The teacher explains what? She explains the use. That is why usum is accusative.

Yes. Usum is the accusative singular of usus, -us, a fourth-declension masculine noun meaning use.

This often surprises learners because -um is very commonly seen in second-declension neuter nouns, but here it is not neuter at all. It is simply the regular accusative singular ending of this fourth-declension noun:

• nominative: usus
• accusative: usum

So usum does not come from a neuter noun; it comes from usus.

Huius vocabuli is in the genitive singular, and it depends on usum.

Latin often uses the genitive where English uses of. So:

• usum huius vocabuli = the use of this word

More specifically:

• huius = of this
• vocabuli = of the word
• together: of this word

So the genitive phrase tells you whose use or what use is being explained.

Because the sentence needs the genitive, not the nominative or accusative.

The phrase means the use of this word, so Latin needs of this, which is genitive singular. The genitive singular of hic, haec, hoc is huius.

So:

• hoc vocabulum = this word
• huius vocabuli = of this word

That is why huius is correct here.

Yes. Huius agrees with vocabuli in number and its basic reference, and together they form the phrase of this word.

A detail that often confuses learners is that huius has the same genitive singular form for masculine, feminine, and neuter. So even though vocabulum is neuter, the form is still huius, not something different.

Because it depends on usum and means of the word.

The dictionary form is vocabulum, -i, a second-declension neuter noun. Its genitive singular is vocabuli.

So:

• vocabulum = word as a basic form
• vocabuli = of the word

In this sentence, Latin expresses the use of this word with usum huius vocabuli.

Clare is an adverb. It modifies the verb explicat and tells us how the teacher explains: clearly.

It comes from the adjective clarus, clara, clarum, meaning clear or bright. A very common way to form adverbs in Latin is to use -e with first-and-second-declension adjectives:

• clarus = clear
• clare = clearly

So clare explicat means explains clearly.

Explicat is:

• present tense
• indicative mood
• active voice
• third person singular

Its dictionary form is explico, explicare, meaning to explain.

The ending -t tells you it is he/she/it explains. Since the subject is magistra, the sense is the teacher explains.

Yes, if the subject were already clear from context. Latin often omits an expressed subject because the verb ending already tells you the person and number.

So explicat by itself already means he/she/it explains. If everyone already knows that the teacher is the one speaking or acting, Latin could simply say:

Usum huius vocabuli clare explicat.

However, including magistra makes the subject explicit.

Latin word order is more flexible than English word order because the endings show grammatical function.

This sentence has a very natural prose order:

• Magistra = subject
• usum huius vocabuli = object with its genitive phrase
• clare = adverb
• explicat = verb

But Latin could rearrange the words without changing the basic meaning, for example:

• Magistra clare usum huius vocabuli explicat.
• Huius vocabuli usum magistra clare explicat.

The main difference would be emphasis, not core meaning.

They are:

• magistra, -ae = female teacher
• usus, -us = use
• hic, haec, hoc = this
• vocabulum, -i = word
• clare = clearly
• explico, explicare = explain

Knowing the dictionary forms helps you recognize why the sentence has the exact forms magistra, usum, huius, vocabuli, clare, and explicat.