The cassock, an item of clerical clothing

Clerical clothing

Clerical clothing is non-liturgical clothing worn exclusively by clergy. It is distinct from vestments in that it is not reserved specifically for services. Practices vary: clerical clothing is sometimes worn under vestments, and sometimes as the everyday clothing or street wear of a priest,...

, is an ankle-length robe

Robe

A robe is a loose-fitting outer garment. A robe is distinguished from a cape or cloak by the fact that it usually has sleeves. The English word robe derives from Middle English robe , borrowed from Old French robe , itself taken from the Frankish word *rouba , and is related to the word rob...

 worn by clerics of the Roman Catholic Church

Roman Catholic Church

The Catholic Church, also known as the Roman Catholic Church, is the world's largest Christian church, with over a billion members. Led by the Pope, it defines its mission as spreading the gospel of Jesus Christ, administering the sacraments and exercising charity...

, Eastern Orthodox Church

Eastern Orthodox Church

The Orthodox Church, officially called the Orthodox Catholic Church and commonly referred to as the Eastern Orthodox Church, is the second largest Christian denomination in the world, with an estimated 300 million adherents mainly in the countries of Belarus, Bulgaria, Cyprus, Georgia, Greece,...

, Anglican Church, Lutheran Church and some ministers and ordained officers of Presbyterian and Reformed churches. Ankle-length garment is the meaning of the corresponding Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 term, vestis talaris. In Western Christianity

Western Christianity

Western Christianity is a term used to include the Latin Rite of the Catholic Church and groups historically derivative thereof, including the churches of the Anglican and Protestant traditions, which share common attributes that can be traced back to their medieval heritage...

 the cassock is generally close-fitting, but in the Eastern Orthodox Church the outer cassock is quite loose.

The cassock derives historically from the tunic

Tunic

A tunic is any of several types of clothing for the body, of various lengths reaching from the shoulders to somewhere between the hips and the ankles...

 that in ancient

Classical antiquity

Classical antiquity is a broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world...

 Rome was worn underneath the toga

Toga

The toga, a distinctive garment of Ancient Rome, was a cloth of perhaps 20 ft in length which was wrapped around the body and was generally worn over a tunic. The toga was made of wool, and the tunic under it often was made of linen. After the 2nd century BC, the toga was a garment worn...

 and the chiton

Chiton (costume)

A chiton was a form of clothing worn by men and women in Ancient Greece, from the Archaic period to the Hellenistic period ....

 that was worn beneath the himation

Himation

A himation was a type of clothing in ancient Greece. It was usually worn over a chiton, but was made of heavier drape and played the role of a cloak.The himation was markedly less voluminous than the Roman toga....

 in ancient Greece.

The word "cassock" comes from Middle French "casaque", meaning a long coat.