A room or a location held for your group alone, with the terms spelled out before a deposit changes hands.
Private is not a standard word. At one location it means a dedicated room while the rest of the business runs normally. At another it means the whole place is closed to other guests for a window. Both are legitimate and they cost and behave differently, so ask which one you are being quoted. Ask what hours the reservation covers, whether setup and cleanup are inside that window, and what happens if you run over.
Capacity is the other question, and it is not one to guess at. How many people the space holds, how many can be served at once, and whether those are the same number are three separate answers. Ask all three. Ask what the deposit is and at what point it becomes non-refundable, and whether that changes closer to the date. And ask what is permitted in the space regarding food and drink — that is set by the location and by state rules, not by what a group would like to bring.
Tell us the occasion, how many people and when you need to be done. We will find the locations that can hold the group and get the terms in writing.
Book the GroupA head count and a date is plenty to start — we will follow up on timeline, deposit and what the location needs to know.