Some interesting facts I found out about the word "martyr".
The word "martyr" is originally synonymous with "witness".
The word "martyr" as we know it was originally referred to as a "red martyr".
Christians referred to as "martyrs" in the original sense of the word became to be called "white martyrs".
St. Justin was called "Justin Martyr" (Iustinus Martyr) in jest because of his "death wish" for red martyrdom. He died of old age, coincidentally.
Eventually, Christians began to use the word "confessor" for "white martyrs" and "martyr" began to denote exclusively "red martyrs".
Cheers,
Colin Michael Bodayle.