Definition

Continuing Airworthiness management is the process by which an aircraft is kept in a condition where it remains airworthy throughout its life - i.e. technically fit for flight. 

In the words of the International Civil Aviation Organisation (ICAO):

“All of the processes ensuring that, at any time in its life, an aeroplane complies with the technical conditions fixed to the issue of the Certificate of Airworthiness and is in a condition for safe operation" - source: ICAO Airworthiness Manual [ICAO, 2014]