The derivation of the term “jack stud” and what it means in modern building construction
In a deck of playing cards, the jack is less valuable than the king—but it still has its own important role to play. And so it is with wall studs.
The jack stud is shorter than the full-length king stud on each side of a window or door opening but critical for holding up the ends of the header that bridges the gap. The jack stud is sometimes called a trimmer stud.

The term “jack” derives from mid–16th century England, where it referred to a lad, knave, or common man:
Jack: (1) A man of the common people, a lad, fellow, chap, especially a low-bred or ill-mannered fellow, a knave. (2) That which takes the place of a lad or man, a machine for lifting weights from below; in building, a small brick or “bat” used as a closer at the end of a course.
In some uses, “jack” has a diminutive force or meaning, denoting things that are smaller or slighter than the normal ones: “jack rafter,” “jack stud.”
Next See:
• What is a Cripple Stud?
• How to Hammer & Pull Nails
• How to Drill a Hole
• How to Cut Drywall
• Wall Materials Buying Guide