Diamond twills: a type of weave in which the warp passes over 1 or 2 and under 2 weft-threads, creating a surface of diamonds.
Fraying: unravelling a piece of fabric
Fulling: treading or beating a piece of fabric to clean or thicken the fabric.
Gusset: Triangular piece of cloth sewn in between front and back panels of a garment to enlarge the garment on one side.
Hem: Border of fabric made by turning the edge inward and sewing it down.
Mitten: glove that encases the thumb separately and the other four fingers together (but I don’t know if this also applies to medieval gloves)
Pattern repeat: Woven patterns are generally repeated at regular intervals. A pattern repeat indicates the amount of warp and weft-threads needed to complete a full pattern and start a new one. A diamond twill with a pattern repeat 20/18 for example means that the diamond is woven using 20 warp- and 18 weft-threads.
Piled weave: Fabric in which loops of threads have been inserted, creating a fur-like appearance.
Raised nap: Roughened surface of a woven fabric, created by brushing it with teasels.
Selvedge: edge of woven fabric, parallel to warp, woven in a way to prevent the edges from fraying. A selvedge is often reinforced to prevent the fabric from stretching.
Shears: cutting instrument with two meeting blades pivoting as in scissors or connected by a spring and passing close over each other edge to edge.
Spin pattern: Pattern in a woven fabric created by using both z- and s-twisted threads in warp or weft or both. The direction of the twist of the threads is clearly visible in the fabric, creating a very subtle pattern.
Tablet weaving or card weaving is a technique in which the loom is replaced by a set of flat rectangular cards or tablets. The longitudinal threads (warp) are passed through holes in the tablets and by turning these tablets a gap or shed is created through which the weft is woven.
Tabby: a type of weave in which the warp alternates with weft every thread. (note font)
Teasels: plant of the genus Dipsacus with prickly leaves and flower heads which have hooked prickles. These flower heads were used to roughen the surface of a woven fabric.
Twill: a type of weave in which the warp passes over 1 or 2 and under 2 or more weft-threads, creating a surface of parallel diagonal ribs.
Warp: longitudinal threads stretched on a loom through which a weaver passes the weft thread.
Weft: threads crossing from side to side interwoven with warp, creating a woven fabric.