(1):

(n.) The state of two nouns or pronouns, put in the same case, without a connecting word between them; as, I admire Cicero, the orator. Here, the second noun explains or characterizes the first.

(2):

(n.) The putting of things in juxtaposition, or side by side; also, the condition of being so placed.

(3):

(n.) The act of adding; application; accretion.