Biology (noun)

1. The study of living organisms and their functions and interactions with each other and the environment.
2. The characteristics and behaviors of a particular type of organism.

Origin:

From the greek βίος (bios) "life" and -λογία (-logia) "study of".

Examples:

1. Biology is the study of living things.
2. I am taking a course in marine biology this semester.
3. The biology of the species is not well understood.
4. A career in biology can take many different forms.
5. The biology of the plant is complex and not fully understood.