noun
unit
YOO-nit/ˈjuːnɪt/
A single part treated as a self-contained whole.
Each wooden block in the row counts as one unit.

Etymology
Unity once named a single number regarded as an undivided whole. Unit developed from that use to mean one separately counted thing or person within a group.
In context
He likes to go from unit to unit. Unit 1, unit 2, unit 3. There's different cameras that show different angles in each unit. We rely on them quite a bit because there are so many inmates to one area.
More examples
- The hospital opens a new unit for heart patients.
- Each rental unit has its own kitchen and bathroom.
- This course has three units, each worth one credit.
Forms
unit · units
unitary adjective — Forming or operating as a single whole.