meaning striving, struggling, endeavoring. Commonly translated as Holy War.
Good introductory articles on this complex issue:
The purpose of jihad influences or should influence even the most intimate aspects of a Muslim's life, e.g. the question whom he should or should not marry. Muhammad put considerable emphasis on marrying women who are able to give birth to many children in order to increase the power of Islam, see BIRTH RATE.
Jihad is also against Muslims: Qur'an 2:278-279, 9:73, 49:9, and Sunan Abu Dawud, Book 26, Number 3675, Sahih al-Bukhari, Volume 9, Book 92, Number 388; cf. the article The war on Muslims, Jihad and the Prophets.
Other keywords in the Quran and hadith:
Narrated Abu Huraira:It is therefore not difficult to understand why some extremist Muslims (eg. the Hamas) were willing to die for their terrorist acts all around the world. They believed that as long as they are fighting Allah's cause, they die for it, they are assured a place in Paradise. However, believing that it is for God's cause does not automatically mean that it really is God's cause.
The Prophet said, "The person who participates in (Holy battles) in Allah's cause and nothing compels him to do so except belief in Allah and His Apostles, will be recompensed by Allah either with a reward, or booty (if he survives) or will be admitted to Paradise (if he is killed in the battle as a martyr). Had I not found it difficult for my followers, then I would not remain behind any sariya going for Jihad and I would have loved to be martyred in Allah's cause and then made alive, and then martyred and then made alive, and then again martyred in His cause." (Sahih al-Bukhari 1.35, also Sahih al-Bukhari 4.386)
[Jesus said:] "Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven. Many will say to me on that day, 'Lord, Lord, did we not prophesy in your name, and in your name drive you out demons and perform many miracles?' Then I will tell them plainly, 'I never knew you. Away from me, you evildoers!'" (Matthew 7:21)