student number (for seating, etc. in class)
 personal identification number;  PIN;  password number
 numbered tag;  numbered ticket
 number on back of player's shirt;  uniform number;  shirt number
 serial number;  consecutive number
 (manufacturer's) serial number
 account number (bank, etc.)
 winning number (e.g. in lottery);  lucky number
 confirmation number;  reservation number;  reference number
 item number;  product ID number;  reference number
 identity number;  national identification number;  national identity number;  personal identity number
 identification number;  confirmation number;  authentication number
 Köchel number (catalogue of Mozart's music)
 national identification number system;  My number system
 personal identification number;  PIN;  password number
 directory or book of numbers (e.g. telephone nos)
 tracking number (e.g. for orders)
 reference number;  order number;  tracking number
 International Standard Book Number;  ISBN
 reference number;  order number;  tracking number
 corporate number;  13-digit identification number for corporations
 station-to-station (comms)
 Post Office box address;  P.O.box address
 reference number;  order number;  tracking number
 reference number;  order number;  tracking number
 physical delivery office number
 relative generation number
 International Standard Serial Number;  ISSN
 tax identification number;  TIN
 external character number
 universal pension number;  common number shared between different pension schemes;  basic pension number
 (mobile phone) number portability (introduced to Japan in October 2005)
 license plate for small vehicles (e.g. subcompact car, motorcycle)
 number sign;  hash sign;  pound sign