A more thorough explanation:

Definition: Existing as a single, undivided entity or relating to a single person or thing, as opposed to a group.

Examples:

• An individual cell is the smallest unit of life.
• She prefers to work on individual projects rather than group assignments.
• Each individual has their own unique personality.

The first example illustrates the first part of the definition, as a cell is an indivisible entity that exists on its own. The second example illustrates the second part of the definition, as the person prefers to work alone rather than in a group. The third example also illustrates the second part of the definition, as each person has their own individual personality that sets them apart from others.