OFFSETTING:
The movement of a component of the tape, usually the adhesive from its proper place to some other position. This transfer may occur during unwinding of the tape or on removal of the tape from a surface to which it has been applied. Offsetting can apply to adhesive transfer, to ink transfer from printed tapes and to transfer from backing coating to the adhesive.

OFF-CORE:
A condition where the tape itself forms a flat-sided roll, but due to a misalignment at the start of winding the core projects from one face.

OHM:
The unit of electrical resistance measurement.

OPACITY:
The ability of a tape to prevent the transmission of light. In practice, opacity is needed when a tape covers printed material or a dark background.

ORGANIC:
Referring to chemical substances based on carbon, other than the simple compounds of carbon and oxygen or elemental metals.

OVEN:
Basically a tunnel enclosure through which the backing is passed to be dried.

OXIDATION:
Reaction of oxygen with any substance. Oxidation of pressure-sensitive adhesives causes them first to soften, then to become hard and non-tacky.

OZONE DETERIORATION:
Breaking down of a rubber or adhesive by the action of ozone in the atmosphere.