Warp: This refers to the yarns that are running the length of the fabric. The are the length of the entire roll.

Fill: These are the yarns that are woven across the width of the fabric. Since cloth rolls are typicaly 54” wide each of these yarns are no longer than that.

Bias: The direction across the sail that’s at a 45^o to the lenth and width of the cloth.

Denier: A system for coding yarn sizes. Low number represent smaller sizes (and more yarns per inch) and larger numbers are for larger yarns (fewer strands per inch).

X-Ply: Strands of fibers run on the bias direction in laminate sails to help reduce bias elongation.

Dacron: DuPont’s trade name for polyester fibers.

Kevlar: DuPont’s trade name for their high strength aramid fibers.

Carbon Fiber: A very strong and elongation resistant fiber used in composite engineering and high end sails, usually but no always racing sails.

Pentex: Modified polyester with 250% less stretch.

Scrim: A Non woven formed sheet held together with resin.

Spectra: Modified polyethylene fiber used mostly in laminate materials but also used in some very high end woven sail cloths.

Taffeta: Light woven fabric used on laminate materials to add durability and abrasion resistance.

Twaron: A family of aramid fibers (like Kevlar) used in racing laminates.

Nylon / Rip Stop: A elastic polymer  that is woven and coated into lightweight fabrics which most spinnakers are made of. They typically are made in such a way as to resist tearing.