Serenity
- Not to be confused with Serenity (agent) or Serenity (Sue).
Serenity is the name of the spaceship that the main characters of Firefly crew, and also where the feature film based on the series gets its title. She is a Firefly-class transport vessel of an older, "aught three" model.
She is also, most memorably once you learn the fact, the Lust Object of Agent Gypsy Roberts. You probably shouldn't ask.