Chant is the rhythmic speaking or singing of words or sounds, either on a single pitch or with a simple melody involving a limited set of notes and often including a great deal of repetition or statis.
Chant may be considered speech, music, or a heightened or stylised form of speech which some people may consider more effective in conveying emotion or expressing, or, getting in touch with, one's spiritual side.
The concept of chantingmantras is of particular significance in many Hindu traditions and other closely related Dharmic Religions, for example the Hare Krishna movement is based almost exclusively around the chanting of Sanskrit Names of God.
Gregorianchant is also known as plainchant or plainsong, and is a form of monophonic, unaccompanied singing, which was developed in the Catholic church, mainly during the period 800-1000.
In all likelihood, chant is at least as old as the breakup of the western Roman Empire in the 5th century, but mutated into different forms in different regions until brought together into one unified repertory under Charlemagne.
Chant is commonly written on a staff similar to the modern 5-line-4-space staff, but the Gregorian staff has 4 lines and 3 spaces.