inclusion

noun8

1. •
   The act of including, i.e. adding or annexing, (something) to a group, set, or total.

   • The inclusion of the poem added value to the course.
2. •
   An addition or annex to a group, set, or total.

   • The poem was a new inclusion in the textbook.
3. •
   Anything foreign that is included in a material.
4. •
   Any material that is trapped inside a mineral during its formation, as a defect in a precious stone.

   • The fewer inclusions a diamond has, the better is its clarity and value. Often the inclusions can be cut out of a diamond in the rough. — 2009
5. •
   A nuclear or cytoplasmic aggregate of stainable substances.
6. •
   An object completely inside a tissue, such as epidermal inclusion cyst, a cyst in the epidermis.
7. •
   A mapping where the domain is a subset of the image.
8. •
   (no longer used) Restriction; limitation.