| Occlusive | A covering (eg wound dressing) to protect and/or heal a moist wound. |
| OEM | "Original equipment manufacturer. In the automotive supply chain, OEMs are vehicle manufacturers." |
| Offshore processing | See outward processing. |
| Oiling | See finish oil. |
| Oleophilic | A propensity to absorb oil. |
| Olefin (also known as polyolefin and polypropylene) | "A manufactured fiber characterized by its light weight, high strength, and abrasion resistance. Olefin is also good at transporting moisture, creating a wicking action. End-uses include activewear apparel, rope, indoor-outdoor carpets, lawn furniture, an |
| Ombré | "A term used to describe fabrics with a dyed, printed or woven design in which the colour is graduated from light to dark and often into stripes of varying shades." |
| Ondé | A fabric with a waved effect produced by calendering or weaving. |
| Open end spinning | A spinning system in which sliver feedstock is highly drafted and thus creates an open end or break in the fibre flow. The fibres are subsequently assembled on the end of a rotating yarn and twisted in. Techniques for collecting and twisting the fibres in |
| Open-end spinning | A spinning system in which sliver feedstock is highly drafted and thus creates an open end or break in the fibre flow. The fibres are subsequently assembled on the end of a rotating yarn and twisted in. Techniques for collecting and twisting the fibres in |
| OPT | See outward processing. |
| Organdy | A plain-weave fabric of light weight and with a permanent stiff finish. |
| Organza | A thin but stiff plain woven silk fabric. |
| Organzine | "A silk yarn used for weaving or knitting. The yarn comprises single threads which are twisted, folded two-, three- or four-fold, and finally twisted in the direction opposite to that of the single yarn." |
| Osnaburg | "A tough medium to heavyweight coarsely woven plain weave fabric, usually made of a cotton or cotton/poly blend. Lower grades of the unfinished fabric are used for such industrial purposes as bags, sacks, pipe coverings. Higher grades of finished osnaburg |
| Ottoman | A warp-faced fabric showing a bold weft-way rib. |
| Outward processing | "A procedure whereby a company based in one country exports material to another country for additional processing, and then reimports the processed products for further treatment, for domestic distribution, or for re-export. The most common form of outwar |
| Oxford | A plain-weave shirting of good quality yarns that has two warp ends weaving as one. |