For Greek and Latin authors of the first centuries CE the Saracens - in Greek οἱ Σαρακηνοί (hoi Sarakēnoi) and in Latin Saracēni – were the tribe or tribes who lived in the Roman province of Arabia Petraea (i.e., the Sinai Peninsula and the northwest part of the Arabian Peninsula).
In the earlier centuries of the medieval period the word came to be applied to Arabs from anywhere in the Arabian Peninsula; and by the 12th century it was used, even more broadly, to refer to Muslims, whether or not they came from Arabia: the word ‘Muslim’ was rarely used, and Muslims were regularly referred to as Saracens, a word with negative associations insofar as it represented Muslims as the enemies of Christianity.
In the contemporary world of sport Saracens is the name of a very successful professional rugby union team (Saracens F C), originally an amateur club founded in London in 1876 by the Old Boys of what later became St Marylebone Grammar School. The club was named in recognition of the military successes of the 12th century Saracen warriors who fought under Saladin (1137-1193) against the Crusaders.
Etymological note: Saracen came into English in the 13th century, through Old French, from Late Latin, but the etymology of the Latin Saraceni and Greek Σαρακηνοί (Sarakēnoi) is uncertain. Some claim that these words derive from the Arabic saraqa (‘to steal’, ‘to plunder’), more specifically from sāriqīn, a plural form of the noun sāriq (‘thief’, ‘plunderer’); but this plausible claim is not universally accepted and several alternative derivations have been proposed.