Martyr

One who bears witness of the truth, and suffers death in the cause of Christ (Acts 22:20; Rev 2:13; Rev 17:6). In this sense Stephen was the first martyr. The Greek word so rendered in all other cases is translated “witness.” (1.) In a court of justice (Matt 18:16; Matt 26:65; Acts 6:13; Acts 7:58; Heb 10:28; 1 Tim 5:19). (2.) As of one bearing testimony to the truth of what he has seen or known (Luke 24:48; Acts 1:8, Acts 1:22; Rom 1:9; 1 Thess 2:5, 1 Thess 2:10; 1 John 1:2).

From Easton’s Bible Dictionary (1897), by Matthew George Easton.