Lena is a very common female Greek name; it derives from the Greek name Eleni. Once upon a time, it used to be the most common diminutive of name Eleni, but today, since most Greek women tend to use their main name instead of some diminutive or nickname, it has become significantly less popular. It is still used though to call a woman named Eleni if someone wants to address her in a more tender way.
Male Version of name Lena: N/A
Nameday of name Lena: May 21st
Origin of name Lena – Agia Eleni – Saint Helen
Since Lena is a diminutive of name Eleni, it is also associated with Agia Eleni, this important personality of the Orthodox and Catholic Christian Religion, known as Saint Helen. You can read more about the name Eleni and its origin, at the pertinent post for the name Eleni.