Yes panto is short for pantomime. Traditionally a Christmas entertainment for the whole family with lots of fairly smutty jokes and audience participation. The leading man is always a woman in tights and the ugly dame is always a man in extremely OTT costume. Best ones I saw were Aladdin in Swansea with Jess Conrad (old 50s/60s pop star) and several in Glasgow with Rikki Fulton et al