What does apposition mean?
The definition of apposition
Ap`po*si”tion, n.
Etym: [L. appositio, fr. apponere: cf. F. apposition. See Apposite.]

1 The act of adding; application; accretion. It grows . . . by the apposition of new matter. Arbuthnot.
2 The putting of things in juxtaposition, or side by side; also, the condition of being so placed.
3 (Gram.)
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. Growth by apposition (Physiol.), a mode of growth characteristic of non vascular tissues, in which nutritive matter from the blood is transformed on the surface of an organ into solid unorganized substance.