Final answer:
The term that best describes a winged seed loosened from its parent stem is Dispersal. Winged seeds are adapted for dispersal by wind.
Step-by-step explanation:
The term that best describes a winged seed loosened from its parent stem is Dispersal. Dispersal is the movement of seeds away from the parent plant, which allows for the colonization of new habitats and reduces competition among offspring. Winged seeds are an adaptation that aids in seed dispersal by wind.