I working at a hotel, and if you were to ask me what is the most common word that I hear every day, it would be: affiliate. The word spans many industries in many dynamic ways, from marketing to religion and beyond, but this creature also blankets metropolitan hotel markets.
Used as a noun in this sense, an "affiliate" or an "ICW" ("in conjunction with") refers to an ancillary meeting taking place simultaneously with a convention or conference. It's smaller in nature, follows topic with the larger event, and often compliments the bigger picture with a branch of education, marketing or networking. (Some are also termed "co-located.)
Affiliated events are set up and executed in various ways, depending on the conference planner's guidelines. Some conventions buy out an entire hotel and rely on affiliates to fill the space and contribute to their food & beverage minimums. The space might be sold and assigned by the convention planner, or the planner may turn the right over to the hotel to do so. Each one is different. Some conventions don't anticipate these ancillary events at all, and it is up to the hotel's Event Manager to work closely with the client to maintain approval for the event to even take place.
Affiliate numbers can add up; for example, my upcoming convention has nearly 60 affiliated events. It's a volume to which our property is accustomed - but many are not. (Smaller metropolitan markets like Denver, Colorado or Austin would fall in the latter category.)
My advice to you? If you don't know anything about affiliate processes, start your research. Consider this your first lesson on affiliates and stay tuned for more to come!