A Baronet is not a baron or a baroness or the lands they hold. Instead it is a slightly lower British rank that lies between baron and knight on the Order of Precedence. Only the Knights of the Garter are above it. It is the lowest hereditary order.
This sense of baronet is also just outside of the SCA period as it was started by James I in 1611, as a quick way of raising income -- you paid, he made. However, the term was also used by Richard II to refer to nobility who lost the right of individual summons to Parliament. Mention is made of baronets in the 14th, 15th and 16th centuries but it is not clear what rights and responsibilities were attached to the title. They do not appear to have been hereditary.