Definitions of effort:

• noun:   use of physical or mental energy; hard work

  Example: "He got an A for effort"

• noun:   earnest and conscientious activity intended to do or accomplish something

  Example: "Made an effort to cover all the reading material"

• noun:   a notable achievement

  Example: "The book was her finest effort"

• noun:   a series of actions advancing a principle or tending toward a particular end

  Example: "Contributed to the war effort"