Learn Hardcore Italian: Domani ci riuniremo in piazza alle otto. - Tomorrow we will meet in the square at eight.

It’s the reflexive/reciprocal clitic for the pronominal verb riunirsi. With a plural subject, it means “we will gather/meet with each other.” Here ci is not “us” as an object and not “there”; it’s part of the verb’s meaning “to get together.”

Can I omit ci and just say Domani riuniremo…?

No. Without ci, riuniremo is transitive: “we will bring together/gather [something/someone].”

Correct for “get together”: Domani ci riuniremo…
Transitive meaning: Domani riuniremo il team (we’ll convene the team).

Could ci here mean “there”?

No. In this sentence ci is reflexive/reciprocal. The locative ci (“there”) typically appears with verbs of movement or staying:

Locative: Ci andiamo alle otto (We’ll go there at eight).
In our sentence, using ci as “there” would be wrong; the ci is required by riunirsi.

Why use the future riuniremo if Domani already indicates the future? Can I use the present?

Both are fine, with a nuance:

Domani ci riuniremo… = planned or promised future; slightly more formal/explicit.
Domani ci riuniamo… = very common in speech for scheduled events (the “present for the future”).

Could I use incontrarci or vederci instead of riunirci? Are there differences?

Yes, with nuance:

riunirsi: “to convene/hold a meeting;” sounds a bit more organized or formal.
incontrarsi: “to meet (each other);” neutral and common.
vedersi: very colloquial “to see each other,” widely used for appointments. Examples:
Domani ci riuniamo in piazza alle otto. (we’re convening)
Domani ci incontriamo/ci vediamo in piazza alle otto. (we’re meeting/seeing each other) Also heard: trovarsi (regional/colloquial) → Domani ci troviamo in piazza alle otto.

Why is it in piazza and not a/alla piazza?

Italian uses in with many public places when the idea is “in/at that place” as the setting: in piazza, in chiesa, in ufficio, in centro.

alla piazza is generally unnatural.
nella piazza is used when specifying a particular, previously identified square (e.g., nella piazza del paese).
Generic meeting point: in piazza is the idiomatic choice.

What if the square has a name? Do I need an article?

Use in Piazza + Name, without the article:

Domani ci riuniremo in Piazza Garibaldi. Note: in Rome you’ll hear a Piazza Navona; it’s a local usage. Standard Italian prefers in Piazza Navona.

What does alle otto literally mean?

It’s a + le (“at the”), because Italian hours are feminine plural (implied (le) ore):

alle due/tre/quattro…
Special cases: all’una (1:00), a mezzogiorno (noon), a mezzanotte (midnight).

How do I say other times like 8:15, 8:30, 7:45?

8:15: alle otto e un quarto / alle otto e quindici
8:30: alle otto e mezza / alle otto e trenta
7:45: alle otto meno un quarto / alle sette e quarantacinque

Can I move the parts around? For example, Ci riuniremo domani alle otto in piazza?

Yes. Word order is flexible for time/place phrases. Natural options include:

Domani alle otto ci riuniremo in piazza.
Domani ci riuniremo in piazza alle otto.
Ci riuniremo in piazza domani alle otto. Keep ci immediately before the conjugated verb (or attached to an infinitive/imperative/gerund).

Where does ci go with other verb forms (infinitives, imperatives, compound tenses)?

Simple tenses: before the verb → ci riuniremo
Compound tenses: before the auxiliary → ci siamo riuniti/e
Infinitive: attach to the end → riunirci (e.g., dobbiamo riunirci)
Progressive: both ci stiamo riunendo and stiamo riunendoci
Imperative: riuniamoci!; plural: riunitevi!; singular: riunisciti!; negative 1st plural: non riuniamoci

Do I need to say noi?

No. The ending of riuniremo already encodes “we.” Noi ci riuniremo… is used only for emphasis or contrast (e.g., “We, as opposed to others, will meet…”).

Do I need a comma after Domani?

Not normally. Domani ci riuniremo… is standard. A comma (Domani, ci riuniremo…) is possible for a pause/emphasis but isn’t required.

How do you pronounce the tricky parts?

ci sounds like “chee.”
riuniremo has five syllables: ri-u-ni-ré-mo (stress on ré).
piazza has zz like “ts” in “pizza.” Putting it together smoothly: ri-u-ni-ré-mo in pi-à-zza al-le òt-to.

Does anything change if the group is all women?

Not in this future form: ci riuniremo stays the same. Agreement shows up with past participles/adjectives:

Mixed or all-male past: Ci siamo riuniti ieri.
All-female past: Ci siamo riunite ieri.

How can I add who we’re meeting with?

Use con:

Domani ci riuniremo con il cliente in piazza alle otto.
Domani ci riuniremo con voi in piazza alle otto.