A composite was a combination of anatomical features.
In 2366, Data programmed several thousand composites for his then-formless child Lal to choose from in USS Enterprise-D's holodeck. Lal ultimately chose a Human female appearance. (TNG: "The Offspring")
Composites[]
Andorian female
Played by Kristina Kochoff
Played by Kristina Kochoff
Human male
Played by an Andy Wiley
Played by an Andy Wiley
Klingon male
Played by an unknown actor
Played by an unknown actor