I am looking for a word that defines an object or thing within another object or thing.
Like in the movie Inception: a dream within a dream.
I am looking for a word that defines an object or thing within another object or thing.
Like in the movie Inception: a dream within a dream.
Recursive might be what you are after.
I would use nested. For example, "a dream nested within another dream".
See, for example, Russian nesting dolls.
The best word will depend on the context. Given the example of a dream within a dream, I assume that you're thinking of a distinct object that is inside another object, not an object which is a part of another object.
An object that is inside another object can be said to be embedded. The inner object can be of the same type as the outer object or of a different type. Some examples of usage include:
Subset is defined as a portion, particularly in mathematics. An example of subset is a classroom to an entire school.
a constituent part or aspect of something more complex
Constituent, subunit, part...
How about this from Merriam Webster
Mise en abyme
- placement at the center of an escutcheon of a smaller copy of the same escutcheon
- containment of an entity within another identical entity
- image of an image
And from Wikipedia, how mise en abyme is used in film:
Mise-en-abîme occurs within a text when there is a reduplication of images or concepts referring to the textual whole.[...] In film, the meaning of "mise en abyme" is similar to the artistic definition, but also includes the idea of a "dream within a dream". For example, a character awakens from a dream and later discovers that s/he is still dreaming.
The article on Wikipedia specifically mentions Inception as an example of this.
A person or thing that is included within a whole
This is also used commonly in science, for example: