Το «όμορφη» είναι επίθετο.

Because όμορφη is being mentioned as a word, not used as an adjective in a normal sentence.

So Το «όμορφη» είναι επίθετο means something like:

• The word/form όμορφη is an adjective.

In Greek, when you talk about a word, it is very common to put the neuter singular article το in front of it.

Because here το does not agree with the adjective form όμορφη.

Instead, the whole quoted word is being treated as a neuter thing: a word, a form, an item of language.

Compare:

• Η λέξη «όμορφη» είναι επίθετο. = The word όμορφη is an adjective.
  Here η agrees with λέξη, which is feminine.

• Το «όμορφη» είναι επίθετο.
  Here the quoted form itself is treated as a neuter item.

So the feminine form of the adjective does not force the article to be feminine in this kind of sentence.

Yes—many Greek adjectives are usually given in three forms:

• όμορφος = masculine
• όμορφη = feminine
• όμορφο = neuter

So όμορφη is specifically the feminine singular nominative form.

The sentence is saying that this particular form, όμορφη, belongs to the category of adjectives.

Here επίθετο is a noun meaning adjective.

So even though English uses the word adjective as a grammar term, Greek does the same with επίθετο.

In other contexts, επίθετο can also mean surname/last name, so context matters. But in this sentence, it clearly means the grammar term adjective.

Because after είναι (is), Greek often uses the predicate noun without an article, especially when giving a classification.

So:

• είναι επίθετο = is an adjective
• είναι ουσιαστικό = is a noun

This is very natural in Greek grammar explanations.

You could also hear είναι ένα επίθετο, but είναι επίθετο sounds more like a straightforward grammatical label.

They show that the word is being mentioned, not used normally.

Compare the difference in English:

• beautiful is an adjective → mentioning the word
• a beautiful house → using the word

Greek often marks this with quotation marks, and standard Greek punctuation usually uses « » rather than English-style quotation marks.

So «όμορφη» tells the reader: we are talking about the word itself.

Yes, absolutely. That is a very clear and natural sentence.

It may even feel easier for learners because it spells everything out:

• Η λέξη = the word
• «όμορφη» = the word being discussed
• είναι επίθετο = is an adjective

So both are possible, but:

• Το «όμορφη» είναι επίθετο is more compact.
• Η λέξη «όμορφη» είναι επίθετο is more explicit.

A simple pronunciation guide is:

• Το → to
• όμορφη → OH-mor-fee
• είναι → EE-ne
• επίθετο → e-PEE-the-to

Very roughly, the whole sentence sounds like:

to OH-mor-fee EE-ne e-PEE-the-to

A more accurate pronunciation in IPA is:

/to ˈomorfi ˈine eˈpiθeto/

Yes. The subject is the single item το «όμορφη», so Greek uses the singular verb είναι (is).

Even though όμορφη is a quoted word and not a normal noun in the sentence, it still counts as one thing being identified, so singular είναι is correct.