Julek is a diminutive form of the names Juliusz or Julian, commonly used in Polish culture. It conveys a sense of familiarity and affection, often used for children or close friends. The name Juliusz itself is derived from the Roman family name Julius, which is believed to be connected to the Greek word 'ioulos,' meaning 'downy-bearded' or 'youthful.' Julian, on the other hand, has Latin origins and means 'belonging to Julius.'