S kolegicom se dogovaram o novom terminu sastanka.

S here means with, and it requires the instrumental case.

• kolegica = colleague (female)
• s kolegicom = with a colleague / with my colleague

So kolegicom is the instrumental singular of kolegica.

This is a very common pattern in Croatian:

• s prijateljem = with a male friend
• s prijateljicom = with a female friend
• s kolegicom = with a female colleague

The verb is dogovarati se / dogovoriti se, which is a reflexive verb. In Croatian, many verbs naturally include se, and you usually cannot just remove it.

Here, dogovarati se means something like:

• to arrange
• to agree
• to make plans together

So:

• dogovaram se = I am arranging / agreeing
• without se, it would sound incomplete or would change the meaning

In this sentence, se is not translated word-for-word into English, but it is required in Croatian.

This is about aspect.

• dogovarati se = imperfective
• dogovoriti se = perfective

In the sentence, dogovaram se shows an ongoing process: I am discussing / arranging / agreeing.

So:

• dogovaram se = I’m in the process of arranging
• dogovorit ću se = I will reach an agreement / I will settle it
• dogovorio sam se = I reached an agreement

Croatian often uses the imperfective present where English uses am + -ing.

The preposition o in this meaning usually means about and requires the locative case.

So:

• o = about
• novom terminu = about the new time/date/slot
• sastanka = of the meeting

Together:

• o novom terminu sastanka = about the new meeting time / about the new date of the meeting

The structure is:

• o + locative
• terminu is locative singular
• sastanka is genitive singular, because it depends on termin: the term of the meeting

Because o requires the locative, and both the adjective and noun must match in case, gender, and number.

Base forms:

• novi = new
• termin = term / appointment / time slot / date

In the locative singular masculine, they become:

• novom
• terminu

So:

• o novom terminu = about the new time/date

This is adjective-noun agreement:

• masculine singular locative
• novom terminu

Because sastanka depends on terminu.

The phrase means:

• termin sastanka = the meeting’s time / the time of the meeting

In Croatian, this kind of of the meeting relationship is usually shown with the genitive:

• sastanak = meeting
• sastanka = of the meeting

So:

• o novom terminu sastanka = about the new time of the meeting

If you said sastanku, that would be a different case and would not fit this structure.

Yes. Vrijeme is the general word for time, but termin is often used for:

• an appointed time
• a scheduled slot
• an appointment
• a date/time arranged for something

So in contexts like meetings, appointments, classes, or interviews, termin is often more natural than vrijeme.

Examples:

• termin sastanka = the meeting time
• termin pregleda = the appointment time for a medical check-up
• novi termin = a new slot / new date / rescheduled time

Croatian clitics like se usually go in the second position of the clause, not necessarily right next to the verb the way English learners might expect.

So:

• S kolegicom se dogovaram...

is normal Croatian word order.

You may think of se as wanting an early position in the sentence. This is part of Croatian clitic placement.

A more neutral English-like word order would still not be preferred if it broke clitic rules.

Usually s and sa both mean with, but sa is mainly used for easier pronunciation before certain consonant combinations.

Here, s kolegicom is the normal form.

You might hear sa in examples like:

• sa sestrom
• sa mnom
• sa školom in some contexts, depending on pronunciation needs

But in this sentence, s kolegicom is the standard choice.

Yes. Kolegica is specifically a female colleague, and kolegicom is its instrumental form.

Compare:

• kolega = male colleague
• s kolegom = with a male colleague
• kolegica = female colleague
• s kolegicom = with a female colleague

So the sentence tells you the speaker is arranging this with a female colleague.

It is a common pattern, yes. Dogovarati se can be followed by o + locative when talking about the topic being discussed or arranged.

Examples:

• dogovaramo se o sastanku = we are discussing/arranging the meeting
• dogovaraju se o detaljima = they are agreeing on the details
• dogovaram se o novom terminu = I’m arranging a new time

You may also see other patterns depending on what follows, but dogovarati se o + locative is very useful and common.