A ledge, raised platform. In the Bible, used to render Hebrew ăzārāh (Vulgate crepido), apparently either of two platforms or stages, surrounding…

a step leading up to an altar; cf. altar stair n.

The steps of an altar. Obsolete (? nonce-use.)

A step or platform upon which an altar is placed; (also) a painting or sculpture on the vertical face of this.

In churches (esp. those of the East), a raised part of the floor in front of a chapel or of the chancel.

By extension: The platform of a lecture hall; the raised floor on which the pulpit and communion table stand in some places of worship.