A chapel is a Christian place of prayer and worship that is usually relatively small. The term has several meanings. First, smaller spaces inside a church that have their own altar are often called chapels; the Lady chapel is a common type of these. Second, a chapel is a place of worship, sometimes interfaith, that is part of a building, complex, or vessel with some other main purpose, such as a school, college, hospital, palace or large aristocratic house, castle, barracks, prison, funeral home, cemetery, airport, or a military or commercial ship. Third, chapels are small places of worship, built as satellite sites by a church or monastery, for example in remote areas; these are often called a chapel of ease. A feature of all these types is that often no clergy were permanently resident or specifically attached to the chapel.

A Lady chapel or lady chapel is a traditional British term for a chapel dedicated to "Our Lady", Mary, mother of Jesus, particularly those inside a cathedral or other large church. The chapels are also known as a Mary chapel or a Marian chapel, and they were traditionally the largest side chapel of a cathedral, placed eastward from the high altar and forming a projection from the main building, as in Winchester Cathedral. Most Roman Catholic and many Anglican cathedrals still have such chapels, while mid-sized churches have smaller side-altars dedicated to the Virgin.