A mascot was an individual or object intended to represent or bring luck to a company or sports team.
Quark considered Morn to be his bar's mascot, going as far as to replace him with a hologram at one point, because, according to Quark, "Everyone who comes in here expects to see him, and if they don't, it doesn't feel like home to them."
After Morn faked his death in 2374, Odo remarked that without Morn as a mascot, business would suffer. (DS9: "Who Mourns for Morn?")
During 32nd century, Starfleet Academy's Laplings team mascot was a Lapling named Lappy, while the War College's Mugatos team mascot was Mugato. The mascot serves is an important role in the game of Calica, as the person who wore the mascot costume serves as the goalkeeper to prevent the target being shot.(SA: "Kids These Days", "Vitus Reflux")
While not specifically referred to as such, Esky was also a mascot for Esquire magazine.
Keenser appeared together with Esurance mascot Erin Esurance in a tie-in game Delta Vega: Meltdown on the Ice Planet (β) for Star Trek.