Definition of appositions:
(n) :
(grammar) A construction in which one noun or noun phrase is placed with another as an explanatory equivalent, both of them having the same syntactic function in the sentence.
(n) :
(grammar) The relationship between such nouns or noun phrases.
(n) :
The quality of being side by side, apposed instead of opposed, next to each other.
(n) :
A placing of two things side by side, or the fitting together of two things.
(n) :
(biology) The growth of successive layers of a cell wall.
(n) :
(rhetoric) Appositio, the addition of an element not syntactically required.