Við hittumst klukkan átján og fórum heim klukkan nítján.

The -st ending is very important here. It shows the verb is in the middle voice, which often gives a reflexive or reciprocal meaning.

• hitta = meet/find someone
• hittast = meet each other, meet up

So við hittumst means we met each other / we met up.

If you said við hittum, that would normally need an object, for example:

• Við hittum hann. = We met him.

Both are in the past tense.

• hittumst = we met / we met up
• fórum = we went

Both forms are also first person plural, so they match við = we.

The dictionary forms are:

• hittast → hittumst
• fara → fórum

So when you look them up, you would usually search for hittast and fara.

Yes. It comes from fara = to go, and its past tense is irregular.

Some useful forms are:

• ég fer = I go
• ég fór = I went
• við förum = we go
• við fórum = we went

So fórum is not built in a fully predictable way from the infinitive fara. It is a form you simply have to learn.

In this sentence, klukkan is part of the normal way to give clock time in Icelandic.

• klukkan átján = at 18:00
• klukkan nítján = at 19:00

Learners often expect a separate word meaning at, but in time expressions like this, klukkan is the standard way to introduce the hour.

Because this sentence uses the 24-hour clock:

• átján = 18
• nítján = 19

So these correspond to:

• 18:00 = 6 p.m.
• 19:00 = 7 p.m.

This is very common in Icelandic, especially when the time should be clear and unambiguous.

Heim means home in the sense of toward home or homewards.

So:

• fara heim = go home

No preposition is needed. This is similar to English, where we also say go home, not go to home.

A very useful contrast is:

• heim = home, toward home
• heima = at home

For example:

• Við fórum heim. = We went home.
• Við vorum heima. = We were at home.

Because the same subject continues across both parts of the sentence.

So Icelandic, like English, can say:

• Við hittumst ... og fórum heim ...
• We met ... and went home ...

You could repeat við, but you do not need to:

• Við hittumst ... og við fórum heim ...

That is grammatical, just less compact.

Not really. Even though the -st ending is related to reflexive or middle meaning, hittast is best understood as its own verb meaning meet each other or meet up.

So it is better to learn:

• hitta einhvern = meet someone
• hittast = meet each other / meet up

instead of trying to translate -st word for word every time.

No, this is very normal Icelandic word order.

The basic structure is:

• Við hittumst klukkan átján
• og fórum heim klukkan nítján

So you have:

• subject: við
• verb: hittumst
• time expression: klukkan átján

Then the second verb phrase is joined with og = and.

Icelandic word order can be flexible, but this sentence is completely standard and natural.

Yes. Icelandic often allows time expressions to move, depending on emphasis.

For example, you may see patterns like:

• Við hittumst klukkan átján.
• Klukkan átján hittumst við.

Both are possible, but if the sentence starts with klukkan átján, Icelandic still keeps the verb in second position, so you get:

• Klukkan átján hittumst við

That verb-second pattern is a key feature of Icelandic.

A simple way to remember it is:

• hitta + object = meet someone
• hittast = meet each other / meet up

Examples:

• Ég hitti Söru. = I met Sara.
• Við hittumst. = We met each other / We met up.

So in your sentence, hittumst is used because the subject is we, and the meaning is reciprocal.