homotopy hypothesis-theorem
delooping hypothesis-theorem
stabilization hypothesis-theorem
n-category = (n,n)-category
n-groupoid = (n,0)-category
Tetracategories are the algebraic definition of higher category for the most general (i.e. weak) 4-categories.
By the discussion at k-tuply monoidal (n,r)-category a tetracategory with a single object may be regarded as the delooping of a monoidal tricategory. This is discussed in (Hoffnung).
tetracategory
The structure of a tetracategories was given by Todd Trimble.
Todd Trimble Notes on Tetracategories
A polished writeup of the definition appears in section 3.2 of