Meaning and name origin
Alastair \a-las-tair, al(a)-stair\ as a girl's name (also used as boy's name Alastair), is of Scottish and Greek origin, and the meaning of Alastair is "man's defender". Scottish variant of Alexander.
Alastair is not a popular first name for females and an equally uncommon surname or last name for all people (2000 U.S. Census).
Displayed below is a comparison of the popularity of the girl name Alastair and its variant forms. The only popular variation form ranked in the Top 1000/100 is Alexander. (2014 statistics).