“Betulah” means a maiden, as the verse describes Rivkah as a na’arah and a betulah.
On the daf / in context: The term betulah in legal contexts is defined as a na’arah rather than a minor or a bogeret; the verse supplies the linguistic support.
Type of Learning
Custom (Bavli — definition of betulah as na’arah)
What Is Learned
In Torah law “betulah” refers to a na’arah; the description of Rivkah as both “na’arah” and “betulah” anchors that definition.