Quick answer
Gleb is a boy name.
Meaning and history
Russian form of the Old Norse name Guðleifr, which was derived from the elements guð "god" and leif "inheritance, legacy". This was the name of an 11th-century saint, a member of the ruling family of Kievan Rus. Along with his brother Boris he was killed in the power struggles that followed the death of his father Vladimir the Great, and he is regarded as a martyr.
Notes and context
Usage: russian | Russian: Глеб