What is Concentration ?
Concentration is (noun) 1. thinking carefully about something A loud conversation in the next room disturbed my concentration. His concentration slipped and he lost the next two games. 2. the grouping of a lot of things in one area the concentration of computer companies in the south of Scotland The concentration of wild animals round the water hole makes it easy for lions to catch their prey.
source: Easier English, Student Dictionary Upper Intermediate Level