An angel is a supernatural being or spirit found in various religions and mythologies. In Abrahamic religions they are often depicted as servants of God and celestial beings who act as intermediaries between heaven and Earth. In Zoroastrianism and Native American religions angels are depicted as a guiding influence or a guardian spirit.
The English word "angel" is derived from the Greek ἄγγελος (angelos), a translation of מלאך (mal'akh) in the Tanakh; a similar term, ملائكة (Malāīkah), is used in the Qur'an. The Hebrew and Greek words in ancient times meant messenger, and depending on the context may refer either to a human messenger or a supernatural messenger. The human messenger could possibly be a prophet or priest, such as Malachi, "my messenger", and the Greek superscription that the Book of Malachi was written "by the hand of his messenger" ἀγγήλου. Examples of a supernatural messenger, are the "Mal'akh YHWH," who is either a messenger from God, an aspect of God (such as the Logos), or God Himself as the messenger (the "theophanic angel.")
The term "angel" has also been expanded to various notions of spirits found in many other religious traditions. Other roles of angels include protecting and guiding human beings, and carrying out God's tasks. The theological study of angels is known as angelology. In art, angels are often depicted with wings on their back, a halo, robes and various forms of glowing light.