Η νονά και ο νονός θέλουν το βαφτιστήρι τους να είναι ήρεμο στη βάφτιση, αλλά όλοι ξέρουν ότι είναι πολύ ζωηρό.

νονά means godmother, νονός means godfather, and βαφτιστήρι means godchild.

In Greek, these are very common family/social words, especially in the context of a baptism. A νονός or νονά is not just someone present at the ceremony; in Greek culture the relationship is often considered important long after the baptism itself.

Greek normally gives each definite noun its own article.

So:

• η νονά = the godmother
• ο νονός = the godfather

Because the two nouns have different grammatical genders, you cannot use just one article for both. Repeating the article is the natural and correct way to say the godmother and the godfather.

Greek articles change for gender, number, and case.

Here:

• η νονά is feminine singular
• ο νονός is masculine singular
• το βαφτιστήρι is neuter singular

English uses just the, but Greek must match the noun grammatically.

Yes. Βαφτιστήρι is a neuter noun, but it can refer to either a male or female godchild.

This is a good example of how grammatical gender and real-life sex are not always the same thing. Even if the child is a boy or a girl, the noun itself is still often neuter, so the words around it also appear in neuter forms.

Because they agree with το βαφτιστήρι.

In Greek, adjectives must match the noun they describe in gender, number, and case. Since βαφτιστήρι is neuter singular, the adjective forms are also neuter singular:

• ήρεμο = calm
• ζωηρό = lively

This happens even when the adjective comes after είναι. Greek still keeps the agreement.

Here τους means their.

Greek usually places these short possessive words after the noun:

• το σπίτι μου = my house
• η φίλη σου = your friend
• το βαφτιστήρι τους = their godchild

So τους is not unusual here at all. It is the normal Greek way to say possession.

Because Modern Greek usually does not use an infinitive the way English does.

English says:

• They want their godchild to be calm

Greek says:

• Θέλουν το βαφτιστήρι τους να είναι ήρεμο

The pattern is:

• θέλω
  • noun/pronoun + να
    • finite verb

So να είναι is the Greek equivalent of English to be in this kind of sentence.

In meaning, it is the one that is calm, so it is the logical subject of να είναι.

But Greek often builds this kind of sentence so that the noun also works with the main verb θέλω. With a different noun, you can see this more clearly:

• Θέλω τον Γιάννη να είναι ήρεμος
  = I want Yannis to be calm

Here τον Γιάννη is clearly in the accusative. In your sentence, το βαφτιστήρι looks the same in nominative and accusative, because many neuter forms are identical in those two cases.

στη is a contraction of σε τη(ν).

So:

• στη βάφτιση = at the baptism / in the baptism ceremony

This is extremely common in Greek:

• στο = σε το
• στη / στην = σε τη(ν)
• στους = σε τους
• στις = σε τις

With events like this, σε often means at.

Yes, but the difference is mostly one of style and register.

• βάφτιση is the everyday modern form
• βάπτιση is more formal or learned

In normal speech, βάφτιση is very natural and very common.

Because όλοι here means everyone or all people.

Greek uses the masculine plural as the default form for a mixed or unspecified group of people. So:

• όλοι = everyone / all of them
• όλα would refer to things, not people

So όλοι ξέρουν means everyone knows.

ότι introduces a clause after ξέρουν, just like English that:

• ξέρουν ότι είναι πολύ ζωηρό
• they know that it is very lively

After verbs like know, say, and think, Greek often uses ότι or πως.

A useful extra note: do not confuse ότι with ό,τι.

• ότι = that
• ό,τι = whatever

Because Greek often leaves subject pronouns out when the subject is already clear from context.

So instead of saying something like they know that it is very lively, Greek simply says:

• ξέρουν ότι είναι πολύ ζωηρό

The listener naturally understands that είναι refers back to το βαφτιστήρι.

Ζωηρό usually means lively, energetic, or full of movement.

For a child, it often suggests someone active and hard to keep still. It can be:

• affectionate
• neutral
• mildly critical, depending on context

In this sentence, because it is contrasted with ήρεμο, the idea is probably that the child is known for being a bit too energetic to stay calm during the baptism.