Oil analysis refers to a process in which used engine oil is tested and analyzed for the presence of contaminants, wear debris, and other characteristics that can provide information about the condition of an engine or machinery. This type of testing can help identify potential problems with the equipment before they become major issues, allowing for preventative maintenance to be performed and extending the life of the machine. Oil analysis is commonly used in industries such as aviation, manufacturing, and transportation to monitor the health of their engines and machinery.