| Raffia | A fibre obtained from the leaves of the raffia palm. |
| Ramie | "A bast fibre similar to flax, the fibre used for making linen textiles." |
| Raschel knit | A two-needle warp knitting system. Raschel warp knits contain inlaid connecting yarns in addition to columns of knit stitches. |
| Ratiné | "A cloth with a rough surface, which has been achieved by finishing and/or the use of fancy yarns." |
| Rayon | "A manufactured fiber composed of regenerated cellulose, derived from wood pulp, cotton linters, or other vegetable matter." |
| Redox | "A type of chemical reaction in which one of the reagents is reduced, while another is oxidised." |
| Redox agent | A substance which promotes redox reactions. |
| Reed | "A device consisting of several wires closely set which separate warp threads in a loom. The reed determines the spacing of the warp threads, guides the weft carrying device, and beats up the weft against the fell of the cloth." |
| Reed width | The width of the fabric in the reed. |
| Regain | The ratio of the weight of water in a material to the oven-dry weight of the material. |
| Reinforcement (composites) | "A fibre which, when encapsulated in a polymer resin matrix, forms a composite or fibreglass laminate." |
| Reinforcement (geotextiles) | "The ability of a geotextile to reduce stresses or contain deformation in geotechnical structures. The geotextile enhances the shear strength of the soil mass by adhering to the adjacent soil layers. The geotextile layers are normally placed across the po |
| Reinforcing component | See reinforcement. |
| Repellency | "The ability of a fabric to resist such things as wetting and staining by water, stains, soil, etc." |
| Resiliency | "The ability of a fabric to spring back to its original shape after being twisted, crushed, wrinkled, or distorted in any way." |
| Resin | "See prepreg, composite; also used as another word for polymer." |
| Resist treatment | A treatment applied to part of a fabric which causes the area treated to resist the take-up of dye. |
| Retention | "The weight of fluid remaining after a freely swollen fibre, yarn or fabric is subjected to a pressure of 0.5 lb/in2." |
| Reticulated foam | Reticulated foams differ from conventional foams in their cell structure. Reticulation is a process in which cell membranes are destroyed in a controlled explosion and then fused with the cell ribs. Reticulation produces open-celled foam which is especial |
| Retting (flax) | The subjection of a crop of flax or deseeded flax straw to chemical or biological treatment in order to make fibre bundles more easily separable from the woody part of the stem. (See also decortication.) |
| Revetment | A support structure in civil engineering made of riprap (coarse armour stone) or concrete. |
| Ribbon yarns | Yarns that are woven or knitted in the form of a ribbon. |
| Rib Knit | A basic stitch used in weft knitting in which the knitting machines require two sets of needles operating at right angles to each other. Rib knits have a very high degree of elasticity in the crosswise direction. |
| Ring spun | "A spinning system in which twist is inserted in a yarn by using a revolving traveller. This method gives a tighter twist than the more modern, faster and usually cheaper open end spinning process." |
| Rip-stop Nylon | "A lightweight, wind resistant, and water resistant plain weave fabric. Large rib yarns stop tears without adding excess weight to active sportswear apparel and outdoor equipment such as sleeping bags and tents." |
| Riser | Structure which holds a pipe that conveys gas or oil from a well to a drilling platform. The riser extends from the sea floor-where it protects the well from seawater-to the platform. |
| Rotor spinning | A method of open end spinning which uses a rotor (a high speed centrifuge) to collect and twist individual fibres into a yarn. |
| Roving | A collection of relatively fine fibrous strands used in the later or final processes of preparation for spinning. |
| RP | "Reinforced plastic. See also FRP, GFRP, GRP." |
| RTM (composites) | "Resin transfer moulding; RTM allows the moulding of components which have complex shapes and large surface areas with a good surface finish on both sides. The process is suited to short and medium runs and is employed in many transport applications such |
| Rubber printing | See foam printing. |
| Ruching | "Adding a frill of lace or other material, often pleated." |