Alexander is a common male first name. It also occurs as a surname.
The name in English is taken from the Latin "Alexander", which is a romanization of the Greek name Αλέξανδρος (Alexandros). Etymologically, the name is a compound of the Greek verb ἀλέξειν (alexein) "to defend" and the noun ἀνδρός (andros), genitive of ἀνήρ (anēr) "man". Thus it may be roughly translated as "protector of man". The term is either a rare type of "inverse tatpurusha" compound, with the modifier in second position (the cognate Sanskrit tatpurusha being *nararakṣa, cf. Ramayana 6.33.45; the exact Sanskrit counterpart would be *rakṣinara, from PIE hleks(i)-hnros), or a worn-down terpsimbrotos type compound, whose original verbal meaning was "he protects men".
The earliest attested record of the name is the Mycenaean Greek of the feminine Alexandra, written in Linear B (The Mycenaean World, by John Chadwick, New York: Cambridge University Press, 1976, 1999).