Wordnet 3.0
NOUN (1)
1. 
 (trademark) a desktop rotary card index with removable cards; 
 usually used for names, addresses, and telephone numbers; 
- Example: "a news reporter has to have a good Rolodex"
The Collaborative International Dictionary of English v.0.48:
Rolodex \Rol"o*dex\ (r[^o]l"[-o]*d[e^]ks), a. [Trade Mark of
   Newell Office Products.]
   A trade name for a type of card file; as, a Rolodex(R) card
   file. Also used informally and improperly as a noun meaning
   Rolodex(R) card file.
   [PJC]
WordNet (r) 3.0 (2006):
Rolodex
    n 1: (trademark) a desktop rotary card index with removable
         cards; usually used for names, addresses, and telephone
         numbers; "a news reporter has to have a good Rolodex"