A interrupção programada termina às dez.

A is the feminine singular definite article, meaning the.

The noun interrupção is feminine, so it takes a:

• a interrupção = the interruption

In Portuguese, nouns have grammatical gender, so the article has to match the noun.

You usually learn the gender together with the noun: a interrupção, not just interrupção.

Many nouns ending in -ção are feminine in Portuguese:

• a interrupção
• a informação
• a estação

So interrupção is feminine, and that affects the article and any adjective that goes with it.

Because adjectives must agree with the noun they describe.

Here, programada describes interrupção, which is:

• feminine
• singular

So the adjective must also be feminine singular:

• a interrupção programada

Compare:

• o corte programado = masculine singular
• a interrupção programada = feminine singular

Not always literally. In this kind of sentence, programada usually means scheduled or planned.

So:

• interrupção programada = scheduled interruption / planned outage / planned interruption

Portuguese often uses programado/programada in places where English would naturally say scheduled.

In Portuguese, adjectives often come after the noun.

So:

• interrupção programada

is the normal order.

English often puts adjectives before the noun:

• scheduled interruption

Portuguese can sometimes place adjectives before the noun, but after the noun is very common and usually the neutral/default choice.

Termina is the 3rd person singular present form of terminar.

The subject is A interrupção programada, which is singular, so the verb must also be singular:

• A interrupção programada termina...

This present tense is often used in Portuguese for scheduled events, just like in English:

• The meeting starts at nine.
• A interrupção programada termina às dez.

Because às is a contraction of:

• a + as = às

When telling time, Portuguese uses a/as before the hour:

• à uma = at one
• às duas = at two
• às dez = at ten

In às dez, the word horas is understood:

• às dez (horas)

So the as comes from the implied plural noun horas.

Because the full idea is really:

• às dez horas = at ten o’clock

Portuguese often leaves out horas when it is obvious. Even when horas is omitted, the contraction stays:

• às dez
• às cinco
• às oito

So às is still there because the structure is based on as horas.

Yes. That is completely correct.

Both are natural:

• termina às dez
• termina às dez horas

Leaving out horas is very common in everyday Portuguese when the meaning is clear.

Yes, often you can.

• A interrupção programada termina às dez.
• A interrupção programada acaba às dez.

Both can mean that the interruption ends at ten.

In many contexts, terminar and acabar are very close in meaning. Sometimes one may sound slightly more formal or more natural depending on the situation, but both are common.

Yes. Portuguese often uses the present tense for timetables, schedules, and fixed future events.

So termina is grammatically present, but it can refer to a future scheduled time:

• The train leaves at six.
• O comboio parte às seis.
• A interrupção programada termina às dez.

This is very normal in both Portuguese and English.

The accent in às marks the contraction and distinguishes it from other forms.

• às = a + as
• it means at the in time expressions like at ten

So in this sentence, às dez means at ten.

The accent is important in writing.

The ç is called cedilha. It makes the c sound like s before a, o, or u.

So:

• interrupção has a ss/s sound near the end

Without the cedilla, the pronunciation would be different.

You will often see ç in words like:

• informação
• diferença
• coração

A rough guide for a native English speaker is something like:

• in-te-rup-SÃW̃

A few important points:

• the ending -ção is nasal
• ç sounds like s
• the stress falls on the last syllable: -ção

European Portuguese pronunciation is often more reduced than Brazilian Portuguese, especially in unstressed vowels, so the beginning may sound less clearly like full i-e-u syllables than you might expect from the spelling.

Normally, you should keep the article:

• A interrupção programada termina às dez.

Leaving it out would usually sound unnatural in standard Portuguese unless you were writing a headline, label, or some kind of notice style.

So for ordinary sentences, use the article.

The given word order is the most natural neutral one:

• A interrupção programada termina às dez.

Portuguese does allow some flexibility, but changing the order usually changes the emphasis or sounds less neutral.

For a learner, the safest pattern is:

• subject + verb + time

So this sentence is a very good standard model to follow.