Longman Dictionary of Contemporary English - pigtail

~ n 1 one of two lengths of hair that have been pulled together on either side of the head and usually plaited (plait1), worn especially by very young girls  (in pigtails)  (Jenny wore her hair in pigtails.) 2 all of the hair pulled to the back of the head and plaited so that it hangs down; braid1 (2) AmE  (- compare bunch1 (5), plait2, ponytail)