1911 Encyclopædia Britannica/Bowtell

BOWTELL, a medieval term in architecture for a round or corniced moulding; the word is a variant of “boltel,” which is probably the diminutive of “bolt,” the shaft of an arrow or javelin. A “roving” bowtell is one which passes up the side of a bench end and round a finial, the term “roving” being applied to that which follows the line of a curve.