Which word indicates something that constitutes a separate entity or part?

The word "discrete" specifically refers to something that is separate and distinct or individually separate from others. It emphasizes individuality, highlighting that the items or entities in question are not connected and do not intermingle, but rather stand alone as separate parts. This term is often used in various contexts like mathematics, where discrete objects or values are clearly distinguishable from one another.

In contrast, the other options imply different relationships or qualities. For instance, "distinct" suggests a clear difference or uniqueness, but it doesn't necessarily convey the idea of separation in the way "discrete" does. "Connected" indicates a relationship or a linking of parts, which is contrary to the notion of being a separate entity. "Unified" denotes a combination or integration of parts into a whole, further affirming the opposite of separation.

Therefore, "discrete" is the most accurate choice for indicating something that constitutes a separate entity or part.