A curse (also called a jinx, hex or execration) is any expressed wish that some form of adversity or misfortune will befall or attach to some other entity—one or more persons, a place, or an object. In particular, "curse" may refer to a wish that harm or hurt will be inflicted by any supernatural powers, such as a spell, a prayer, an imprecation, an execration, magic, witchcraft, God, a natural force, or a spirit. In many belief systems, the curse itself (or accompanying ritual) is considered to have some causative force in the result. To reverse or eliminate a curse is called removal or breaking, and is often believed to require equally elaborate rituals or prayers.The word "curse" may also refer to the resulting adversity; for example, menstruation has been described as the "curse of Eve".The study of the forms of curses comprise a significant proportion of the study of both folk religion and folklore. The deliberate attempt to levy curses is often part of the practice of magic. In Hindu culture the Sage or Rishi is believed to have the power to bless and curse. Examples include the curse placed by Rishi Bhrigu on king Nahusha and the one placed by Rishi Devala. Special names for specific types of curses can be found in various cultures: