Il glossario spiega la terminologia dell'intervento.

In Italian, articles are used more often than in English. So where English might say Glossary explains... in a heading or very compact style, normal Italian usually says Il glossario spiega...

Here, il is the masculine singular definite article, meaning the.

• il glossario = the glossary

Since glossario is a masculine singular noun, il is the correct article.

Spiega is the third-person singular present tense of the verb spiegare (to explain).

So:

• io spiego = I explain
• tu spieghi = you explain
• lui/lei spiega = he/she/it explains

In this sentence, the subject is il glossario, which is singular, so spiega is the correct form:

• Il glossario spiega... = The glossary explains...

Terminologia is a feminine singular noun, so it takes the article la.

• la terminologia = the terminology

Italian often uses the definite article where English also uses it, especially in a full sentence like this.

Also, terminologia is singular in Italian, just as terminology is singular in English. It refers to a whole set of technical terms, not to one single term.

Dell' is a contraction of:

• di + l' = dell'

It usually means of the.

So:

• dell'intervento = of the intervention

The apostrophe appears because the article l' is used before a noun beginning with a vowel.

Because intervento begins with a vowel (i), Italian uses l' as the definite article:

• l'intervento

When di combines with l', the result is:

• di + l' = dell'

So the correct form is:

• dell'intervento

Not:

• del intervento

Compare:

• del libro = of the book
• dell'intervento = of the intervention

Intervento is a masculine singular noun.

Its basic meaning is intervention, but depending on context it can refer to things like:

• a medical procedure
• a formal speech or contribution in a discussion
• an action taken in a situation
• a specific operation or treatment

So in this sentence, terminologia dell'intervento means the terminology related to the intervention/procedure/action, depending on the context already given.

Italian often uses di to express the relationship that English might show with of or sometimes with a noun used as an adjective.

So:

• la terminologia dell'intervento = the terminology of the intervention

English might also say something like the intervention terminology, but Italian normally prefers the noun + di + noun structure.

This is very common in Italian:

• il titolo del libro = the title of the book
• la porta della casa = the door of the house
• la terminologia dell'intervento = the terminology of the intervention

Yes, it is completely normal.

The structure is:

• Il glossario = subject
• spiega = verb
• la terminologia dell'intervento = object

So it follows a standard subject + verb + object pattern, just like English:

• The glossary explains the terminology of the intervention.

This makes it a very straightforward sentence grammatically.

A helpful approximate pronunciation is:

• glossario ≈ glohs-SAH-ryo
• intervento ≈ een-tehr-VEHN-to

A few useful pronunciation notes:

• In glossario, the gl is a hard g + l sound, not like the gli sound in words such as famiglia.
• The stress in glossario falls on -sa-.
• In intervento, the stress falls on -ven-.
• Italian vowels are usually clear and pure, without the diphthong-like glide often heard in English.

Yes, that would also be grammatical, but it means something slightly different.

• la terminologia = the terminology, the set/system of specialized terms
• i termini = the terms, the individual words

So:

• Il glossario spiega la terminologia dell'intervento focuses on the terminology as a whole.
• Il glossario spiega i termini dell'intervento focuses more on the specific terms.

Both are possible, but terminologia sounds a bit more formal and technical.

Usually, yes: nouns ending in -o are often masculine, and glossario is one of them.

So:

• il glossario
• un glossario

But it is still best to learn each noun together with its article, because Italian has exceptions. In this case, though, glossario is a regular masculine noun.