Definition
The lengthwise (warp) and crosswise (woof) threads that form a woven fabric. The woof, also called the weft or fill, runs across the width of the fabric, perpendicular to the warp threads which run the length of the bolt.
Plain English
The threads in a piece of woven cloth that run side to side, crossing over and under the threads that run the long way.
Context Anchor
Seen in aircraft fabric covering, fabric repair, and inspection of woven covering materials.
Derivation
From Old English 'wefan,' meaning to weave. The woof is literally the 'woven-across' part of a cloth. Same root as 'weft,' which is the more common modern term outside aviation.
Why Pilots Care
On fabric-covered aircraft, the orientation of the warp and woof affects how the fabric stretches, shrinks, and carries load. Applying covering material in the wrong orientation can compromise the strength and tautness of the finished surface.
Intuition Check
Woof does not mean a dog’s bark here. In this maintenance context, it means the crosswise threads in woven aircraft fabric.
Example Sentence 1
When applying the covering to the wing, the technician aligned the warp threads spanwise and the woof threads chordwise per the manufacturer's instructions.
Example Sentence 2
Damage to the woof threads required a new section of covering material.