| BOW |  |
Warp
on the face of a board from end to end. |
| CROOK |
|
Warp along the edge line; also known as crown. |
| CUP |  |
Hollow across the face of a board. |
| TWIST |
|
Multiple bends in a board. |
| KNOT
or KNOTHOLE |
|
A tight knot is usually not a problem; a loose or dead knot, surrounded by a dark ring, may fall out or may have already left a hole. |
| SPLIT |
|
Crack going all the way through the piece of wood, commonly at the ends. |
| CHECK |
|
Crack along the wood's annual growth rings, not passing through the entire thickness of the wood. |
| SHAKE |
|
Separation of grain between the growth rings, often extending along the board's face, and sometimes below its surface. |
| WANE |
|
Missing wood or untrimmed bark along the edge or corner of the piece. |
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