In Christianity, a martyr is a person considered to have died because of their testimony for Jesus or faith in Jesus. In years of the early church, stories depict this often occurring through death by sawing, stoning, crucifixion, burning at the stake or other forms of torture and capital punishment. The word martyr comes from the Koine word μάρτυς, mártys, which means "witness" or "testimony".
At first, the term applied to the Apostles. Once Christians started to undergo persecution, the term came to be applied to those who suffered hardships for their faith. Finally, it was restricted to those who had been killed for their faith. The early Christian period before Constantine I was the "Age of Martyrs". "Early Christians venerated martyrs as powerful intercessors, and their utterances were treasured as inspired by the Holy Spirit."
In western Christian art, martyrs are often shown holding a palm frond as an attribute, representing the victory of spirit over flesh, and it was widely believed that a picture of a palm on a tomb meant that a martyr was buried there.
The use of the word μάρτυς (mártys) in non-biblical Greek was primarily in a legal context. It was used for a person who speaks from personal observation. The martyr, when used in a non-legal context, may also signify a proclamation that the speaker believes to be truthful. The term was used by Aristotle for observations, but also for ethical judgments and expressions of moral conviction that can not be empirically observed. There are several examples where Plato uses the term to signify "witness to truth", including in Laws.
The Greek word martyr signifies a "witness" who testifies to a fact he has knowledge about from personal observation. It is in this sense that the term first appears in the Book of Acts, in reference to the Apostles as "witnesses" of all that they had observed in the public life of Christ.