If two noun groups referring to the same person or thing are in apposition, one is placed immediately after the other, with no conjunction joining them, as in 'Her father, Nigel, left home three months ago.'
英英词典释义
Noun
1. a grammatical relation between a word and a noun phrase that follows;
"`Rudolph the red-nosed reindeer' is an example of apposition"
2. (biology) growth in the thickness of a cell wall by the deposit of successive layers of material
3. the act of positioning close together (or side by side);
"it is the result of the juxtaposition of contrasting colors"