In Indian architecture, gavaksha or chandrashala (kudu in Tamil, also nāsī) are the terms most often used to describe the motif centred on an ogee, circular or horseshoe arch that decorates many examples of Indian rock-cut architecture and later Indian structural temples and other buildings. In its original form, the arch is shaped like the cross-section of a barrel vault. It is called a chaitya arch when used on the facade of a chaitya hall, around the single large window. In later forms it develops well beyond this type, and becomes a very flexible unit, "the most common motif of Hindu temple architecture". Gavākṣha (or gavaksa) is a Sanskrit word which means "bull's or cow's eye". In Hindu temples, their role is envisioned as symbolically radiating the light and splendour of the central icon in its sanctum. Alternatively, they are described as providing a window for the deity to gaze out into the world.

Like the whole of the classic chaitya, the form originated in the shape of the wooden thatched roofs of buildings, none of which have survived; the earliest version replicating such roofs in stone is at the entrance to the non-Buddhist Lomas Rishi Cave, one of the man-made Barabar Caves in Bihar.

The "chaitya arch" around the large window above the entrance frequently appears repeated as a small motif in decoration, and evolved versions continue into Hindu decoration, long after actual chaityas had ceased to be built. In these cases it can become an elaborate cartouche-like frame, spreading rather wide, around a circular or semi-circular medallion, which may contain a sculpture of a figure or head. An early stage is shown in the entrance to Cave 9 at the Ajanta Caves, where the chaitya arch window frame is repeated several times as a decorative motif. Here, and in many similar early examples, the interior of the arch in the motif contains low relief lattice imitating receding roof timbers (purlins).