'bob' is an old word for cutting a horse's tail short. First use of the verb in relation to women's hair 1918; first use of it as a noun, 1926. I'm going to have to redesign my shelves - my etymology dictionary is currently in a place I can only reach with my right hand, and my elbow's been giving me gyp, and by kneeling on the sofa, and I've got bites on my knees which really don't like being knelt on at the moment.
I mention this just to give you some idea of the agonies I go through to look up hairdressing terms.
On the plus sign I didn't need an anaesthetic at the dentist today. He was drilling by hand, not machine, trying to extract something from a root with a long pin thing, and it took ages (in fact this is the third session in whch he's been doing it, three weeks to dig three millimetres he says). Still another couple of sessions to go before I actually get a crown in place. Sigh.