Definition of "Ysabel"

R. Jeeves: In my experience, ladies who spell Gladys with a W are seldom noted for their reliability, sir. It gives them romantic notions.B.W. Wooster: With a W, Jeeves? No, no, no, no. You spell it with a G.R. Jeeves: If I might draw your attention to the signature on the portrait, sir.B.W. Wooster: Good Lord! G-W?R. Jeeves: I blame Alfred Lord Tennyson and his Idylls of the King. It also accounts for Kathryn, Ysabel, and Ethyl, all spelt with a Y, but Gwladys is a particularly virulent form, sir.

1993 May 16, “Return to New York”, in Jeeves and Wooster, Series 3, Episode 6