Glossary
Carpenter Terms & Vocabulary
15 essential carpenter terms with plain-English definitions: the vocabulary you’ll hear in training and on day one.
Key carpenter vocabulary
These 15 terms come up constantly in carpenter training, on the job and in interviews. Knowing them helps you follow instructions, document accurately and sound prepared.
- 3-4-5 method
- Using a 3:4:5 triangle to confirm a right angle.
- Header
- A beam over a door or window opening that carries the load above.
- Joist
- A horizontal member that supports a floor or ceiling.
- Kerf
- The width of the cut a saw blade removes.
- Level
- Perfectly horizontal.
- Load-bearing wall
- A wall that supports weight from above.
- Nominal size
- The name size of lumber (2x4) versus actual size (1.5 by 3.5 inches).
- On center (OC)
- The spacing between the centers of framing members, such as 16 inches OC.
- Plumb
- Perfectly vertical.
- Rafter
- A sloped framing member that supports a roof.
- Rough opening
- The framed opening sized for a door or window.
- Sheathing
- Plywood or OSB panels attached to framing for strength.
- Square
- Corners at exactly 90 degrees.
- Stud
- A vertical framing member in a wall, usually 2x4 or 2x6.
- Top and bottom plates
- Horizontal framing members at the top and bottom of a wall.
Practice these terms
Test yourself with the free Carpenter practice test: it includes vocabulary questions built from this list. For a complete course, see Carpenter training.
Browse terms from every career in our career glossary.