TEHRAN -- Shahid meaning martyr has two meanings in the Islamic culture. In its specific concept, Shahid is someone who is killed on the battlefield for the cause of God.
In its broader concept, anyone who is killed while fulfilling his duty on the path of the truth is considered a martyr. 
Many people are killed for different reasons every day. But which one of them can be called a martyr?
People who are killed can be divided into different categories. Some are killed unintentionally in incidents like bombings by the enemy. These are martyrs but do not have the status of those martyred on the battlefield.
There are also those killed while defending their legitimate rights against oppressors. They also have a lower status than the third group.
The third group is those who are killed or die on the path of fulfilling a divine duty. 
The Holy Qur’an says in Verse 100 of Surah an-Nisa: “One who abandons his home for the cause of God will find many places of refuge in the vast land and one who dies, after having abandoned his home to get near to God and His Messenger, will receive his reward from God. God is All-forgiving and All-merciful.”
According to a Hadith, the Holy Prophet (Peace be upon Him) said: “One who dies on the path of learning knowledge has died as a martyr.”
The fourth group is the believers who are killed while fighting on the battlefield just to gain God’s satisfaction. They will attain the highest rank in martyrdom:
“God has purchased the souls and property of the believers in exchange for Paradise. They fight for the cause of God to destroy His enemies and to sacrifice themselves.” (Verse 111 of Surah at-Tawbah)
Now if someone in the army of Muslims is killed while fighting with intentions other than divine purposes, he will certainly not be a martyr.
So all in all, the main criterion in martyrdom is the intention of the person and not just being killed. That is why when the Qur’an speaks about those killed on the battlefield, it immediately adds “on the path of God”. Hence the criterion for martyrdom is the intention to gain God’s satisfaction.
Another point is that in the Islamic culture, the word Shahid has two meanings: General and specific. In the specific term, Shahid is someone who is killed on the path of God. In general terms, Shahid is someone who is killed while fulfilling a duty. Those who believe in the truth and tread the path of the truth will be considered a martyr if die on this path.
The Holy Qur’an, in Surah an-Nisa, introduces those who follow God and His messenger as companions of prophets, martyrs and pious:
“Whosoever obeys Allah, and the Messenger, they are with those whom Allah has favored, the Prophets, the sincere, the martyrs and the righteous, and these are the best company.” (Verse 69 of Surah An-Nisa)
In Verse 19 of Surah al-Hadid, God equates the true believers with the sincere and martyrs:
“Those who believe in God and His Messenger are the truthful ones and are witness (to the deeds of others) before their Lord. They will have their reward and their light.”