Acts 1:15

καὶ ἐν ταῖς ἡμέραις ταύταις ἀναστὰς Πέτρος ἐν μέσῳ τῶν μαθητῶν εἶπεν· ἦν τε ὄχλος ὀνομάτων ἐπὶ τὸ αὐτὸ ὡς ἑκατὸν εἴκοσιν·

At that time, Peter got up among the disciples (there were about 120 people present) and said -  (NIV)

This verse is confusing for a couple reasons. 

First, because it is incomplete without verse 16.  (Sometimes one wonders at the verse choices made by early editors.  Admittedly, 15 and 16 together would be quite long.) 

Secondly, the 'number of people' expression.  I used the New International Version in the translation above, not because it was the closest to the Greek, but because it was the simplest.  The Greek, word for word, says something like this:

ἦν τε ὄχλος ὀνομάτων 

it was a crowd of names

ἐπὶ τὸ αὐτὸ ὡς ἑκατὸν εἴκοσιν

upon the same as / about one hundred twenty

We can conclude that there were about 120 people present when Peter spoke, but the phrasing in Greek resists idiomatic English.  The King James has

the number of names together were about an hundred and twenty

which includes the translation of ὀνομάτων ('names'), but English does not usually describe a group of people as a group of names.

So it goes in translation.  

Verbs

The main verb for the verse is the familiar aorist active εἶπεν - 'he/she/it said'.

The form ἀναστάς is an aorist active participle (masculine singular nominative) of the -μι verb ἀνίστημι, 'I make stand, I stand'.  This is a tricky verb, not only in morphology, but in meanings; I'll say more about it in the next post.

Nouns

The masculine noun ὄχλος is probably familiar to even beginning students of koine; it is used about 175 times in the New Testament, with the usual translation being 'crowd', or 'multitude'. 

We'll also look at the neuter noun ὄνομα in more detail in a later post.

A final note: manuscripts vary as to how they describe the people Peter was talking to: some say that he spoke ἐν μέσῳ τῶν μαθητῶν (in the middle of the disciples), and others say ἐν μέσῳ τῶν ἀδελφῶν (in the middle of the brothers).