Meaning and name origin
Aleksei \a-lek-sei, al(e)-ksei\ as a boy's name is of Greek origin, and the meaning of Aleksei is "defender". Aleksei is a variant of Alexis (Greek): often used as a short form of Alexander, though it is from Alexius, the Latin spelling of the Greek Alexios. Not frequently used as a name for baby boys.
Aleksei is not a popular first name for males and an equally uncommon surname or last name for all people (Source: 2000 U.S. Population Census).
Displayed below is a comparison of the popularity of the boy name Aleksei and its variant forms. The only popular variation form ranked in the Top 1000/100 is Alexis (#302). (Source: 2014 Birth Name Statistics).