"The literal definition of the word jihad is: striving to achieve a goal, while the Quranic definition of the word is “striving with one’s self and one’s money in the cause of God”.
This Quranic definition is confirmed in a number of Quranic verses which speak of jihad. The following are some examples:
“The true believers are those who believe in God and His messenger, then attain the status of having no doubt whatsoever, and strive (jahadu) with their money and their lives in the cause of God. These are the truthful ones.” 49:15
“Those who believe, and emigrate, and strive (jahadu) in the cause of God with their money and their lives, are far greater in rank in the sight of God. These are the winners.” 9:20
“As for the messenger and those who believed with him, they eagerly strive (jahadu) with their money and their lives. These have deserved all the good things; they are the winners.” 9:88"
http://www.quran-islam.org/articles/part_3/the_concept_of_jihad_(P1360).html