El reflector brilla de noche.

Because reflector is a masculine noun in Spanish, so it takes el.

A useful pattern:

• Many nouns ending in -or are masculine:
  • el color
  • el motor
  • el doctor
  • el reflector

So the article has to match:

• el reflector
• not la reflector

Reflector is a noun, and in Latin American Spanish it can refer to a reflector, lamp, spotlight, or sometimes similar lighting equipment, depending on context and country.

So even if you already know the meaning in this sentence, it helps to know that the word may be a little broader in real-life use than the English word reflector.

It is also a masculine noun:

• el reflector
• los reflectores

Because the subject is el reflector, which is third person singular: it shines.

The verb comes from brillar = to shine.

Present tense:

• yo brillo = I shine
• tú brillas = you shine
• él / ella / usted brilla = he / she / it / you shine

Since el reflector is singular, Spanish uses brilla.

Yes. Brillar is a regular -ar verb.

Its present-tense forms are:

• yo brillo
• tú brillas
• él / ella / usted brilla
• nosotros brillamos
• ustedes brillan
• ellos brillan

So brilla is exactly what you would expect from a regular -ar verb.

Because Spanish usually does not need subject pronouns unless they are needed for emphasis, contrast, or clarity.

In English, you must say:

• It shines at night.

In Spanish, the verb ending often gives enough information, and here the subject noun is already stated:

• El reflector brilla de noche.

Adding a pronoun would usually sound unnecessary:

• El reflector él brilla... ← not natural

Spanish normally just uses the noun:

• El reflector brilla...

De noche is a very common time expression meaning something like:

• at night
• by night
• during the night

It functions as an adverbial phrase telling when the action happens.

So in:

• El reflector brilla de noche

de noche tells you when it shines.

Because de noche is simply the normal Spanish expression.

Languages do not always match word for word:

• English: at night
• Spanish: de noche

Here, de is part of an idiomatic time phrase. It does not literally work the same way as English of or from in this sentence.

Other common expressions like this include:

• de día = during the day / by day
• de mañana = in the morning (in some regions/contexts)

So the best approach is to learn de noche as a set phrase.

Yes, but they are not always used in exactly the same way.

• de noche = at night, by night, nighttime in a general sense
• por la noche = in the evening / at night
• en la noche = at night / during the night, used more in some regions than others

For this sentence, de noche sounds very natural because it describes a general characteristic:

• El reflector brilla de noche.

That feels like:

• The reflector shines at night.

If you said por la noche, it could also sound fine in many contexts, but de noche is especially common for general habits or typical situations.

Because in the fixed expression de noche, Spanish normally does not use an article.

Compare:

• de noche = at night
• de día = during the day / by day

But in other expressions, you may see an article:

• por la noche = at night / in the evening
• durante la noche = during the night

So it is not that noche can never take an article. It is just that de noche is a standard expression without one.

A simple pronunciation guide:

• brilla ≈ BREE-yah in many Latin American accents

Important points:

• br is pronounced together, like in breeze, but with a Spanish r
• i sounds like ee
• ll in most of Latin America sounds like y
• stress falls on the first syllable: BRI-lla

So:

• brilla → BRI-ya

Depending on the country, ll can sound slightly different, but y is a good practical pronunciation for most learners.

A learner-friendly approximation is:

el reflec-TOR BRI-ya de NO-che

A few notes:

• reflector has stress on the last syllable: reflec-TOR
• brilla has stress on BRI
• noche has stress on NO

A rough English-style guide:

• El = ehl
• reflector = reh-flek-TOR
• brilla = BREE-yah
• de noche = deh NO-cheh

It can definitely be used for things.

Brillar means to shine, so it can describe:

• lights
• metal objects
• the sun
• stars
• eyes
• surfaces
• reflectors or lamps

Examples:

• La luna brilla. = The moon shines.
• El metal brilla. = The metal shines.
• Las luces brillan de noche. = The lights shine at night.

So using brilla with reflector is completely normal.

The plural would be:

• Los reflectores brillan de noche.

Changes:

• el → los
• reflector → reflectores
• brilla → brillan

That is because the subject becomes plural, so the verb must also become plural.

Usually it sounds like a general fact or a habitual truth.

• El reflector brilla de noche.

This most naturally means something like:

• it shines at night in general
• it is the kind of thing that shines at night

Spanish present tense often covers both:

• general truths
• habits
• actions happening now

But with de noche, this sentence most naturally feels general, not like a one-time event happening at this exact moment.