Ο ανακλαστήρας είναι κόκκινος.

Ο is the definite article in Greek, meaning the.

In this sentence, ο ανακλαστήρας means the reflector.

A few useful details:

• ο = masculine singular nominative the
• It matches the noun ανακλαστήρας, which is a masculine singular noun
• At the start of a sentence it is written Ο, but otherwise it would normally be lowercase: ο

Greek articles change according to gender, number, and case, much more than English the does.

The ending -ας is a very common ending for a masculine noun in Greek.

So ανακλαστήρας is a masculine singular noun, and here it is in the nominative case because it is the subject of the sentence.

That is why the article is also masculine nominative singular: ο ανακλαστήρας.

It is in the nominative case.

You can tell because:

• it is the subject of the sentence
• the article ο is the masculine singular nominative article
• the noun is in its basic dictionary-style form here

So the structure is:

• ο ανακλαστήρας = the subject
• είναι = is
• κόκκινος = red

In a normal sentence like this, είναι is needed. It is the 3rd person singular form of είμαι, meaning to be.

So:

• είμαι = I am
• είσαι = you are
• είναι = he/she/it is

Greek usually does not omit is in standard sentences the way some languages do. So Ο ανακλαστήρας κόκκινος would sound incomplete in ordinary usage.

Because adjectives in Greek must agree with the noun they describe in:

• gender
• number
• case

Here, ανακλαστήρας is masculine singular nominative, so the adjective also appears in the masculine singular nominative form:

• κόκκινος = masculine
• κόκκινη = feminine
• κόκκινο = neuter

So Greek says, in effect, the reflector is red-masculine, because the adjective matches ανακλαστήρας.

Yes. Absolutely.

In Greek, adjectives agree with the noun whether they are:

• attributive: directly next to the noun
  
  • ο κόκκινος ανακλαστήρας = the red reflector
• predicative: after είναι
  
  • ο ανακλαστήρας είναι κόκκινος = the reflector is red

So even after είναι, the adjective still matches the subject in gender, number, and case.

Yes, Greek word order is more flexible than English.

The most neutral order here is:

• Ο ανακλαστήρας είναι κόκκινος.

But you might also hear:

• Κόκκινος είναι ο ανακλαστήρας.

That version gives more emphasis to κόκκινος.

Even when the order changes, the endings help show what each word is doing, so Greek relies less on word order than English does.

A simple pronunciation guide would be:

• Ο = o
• ανακλαστήρας = a-nak-la-STEE-ras
• είναι = EE-ne
• κόκκινος = KO-kkee-nos

A few pronunciation notes:

• The accented syllable is the one you stress:
  • ανακλαστήρας
  • είναι
  • κόκκινος
• αι in είναι is pronounced like e in modern Greek
• κκ is written double, but in normal speech you usually do not lengthen it dramatically

The accent marks show which syllable is stressed.

So:

• ανακλαστήρας
• είναι
• κόκκινος

Stress is important in Greek, and it is written clearly. This is very helpful for learners, because unlike English, Greek normally tells you where the stress goes.

No. It is capitalized here only because it is the first word of the sentence.

Normally, it is written ο.

For example:

• Ο ανακλαστήρας είναι κόκκινος.
• Βλέπω τον ανακλαστήρα.

In the second example, the article is lowercase because it is not at the beginning.

Yes, but the meaning would change.

• Ο ανακλαστήρας είναι κόκκινος. = The reflector is red.
• Ένας ανακλαστήρας είναι κόκκινος. = A reflector is red or One reflector is red, depending on context

So ο makes the noun definite, while ένας makes it indefinite.

Yes. Κόκκινος is the standard everyday word for red.

Like many Greek adjectives, it changes form depending on the noun:

• κόκκινος = masculine
• κόκκινη = feminine
• κόκκινο = neuter

So you learn the basic meaning as red, but in actual sentences you choose the form that matches the noun.

The pattern is:

article + noun + form of to be + adjective

So here:

• Ο = article
• ανακλαστήρας = noun
• είναι = form of to be
• κόκκινος = adjective

This is a very common Greek sentence pattern and a useful model for making your own sentences, such as:

• Ο ουρανός είναι μπλε. = The sky is blue.
• Το αυτοκίνητο είναι μεγάλο. = The car is big.
• Η πόρτα είναι ανοιχτή. = The door is open.