Opaque glaze

A nontransparent colored or colorless glaze. (ASTM C 242).

Open time

The period of time during which the bond coat retains its ability to adhere to the tile and bond the tile to the substrate.

Orangepeel

A pitted texture of a fired glaze resembling the surface of rough orange peel. (ASTM C 242)

Organic adhesive

A prepared organic material, ready to tire with no further addition of liquid or powder, itsed for bonding tile to hack-up material by the thinset method. Cures or sets by evaporation.

Oven ware

Ceramic whiteware for culinary oven use. (ASTM C 242).

Overglaze decoration

See Decoration, overglaze.