What do you call a vertical framing member extending from the soleplate to the header?

The vertical framing member that extends from the soleplate to the header is specifically referred to as a jack stud. Jack studs serve to support the header above doorways or windows by transferring the load to the soleplate.

While trimmer studs and cripple studs also play important roles in framing, they are not used in the same way as jack studs. Trimmer studs are vertical members that support the ends of a header, while cripple studs are shorter vertical members located above a header or below a window sill.

It's crucial to use the correct terminology in construction to ensure clarity in communication and understanding of structural requirements. In this case, the correct term is jack stud, as it directly describes the member that connects the soleplate to the header.