Longman Dictionary of Contemporary English - number one

~1 n 1 the most important or successful person or thing  (George is number one in this organization. | Kline had so many great plans - number one being to star in a movie.) 2 the musical record that is the most popular at a particular time  (number one in the charts) 3 look out for number one/look after number one spoken to look after yourself and not worry about other people  (Suzanne's only bothered about looking after number one.) ~2 adj 1 most important or successful in a particular situation  (Obedience was the organization's number one priority. | Sweden's number one model) 2 first on a list of several things to be considered, done etc  (item number one on the agenda)