The Collaborative International Dictionary of English v.0.48:
Bairn \Bairn\ (b[^a]rn), n. [Scot. bairn, AS. bearn, fr. beran to bear; akin to Icel., OS., & Goth. barn. See Bear to support.] A child. [Scot. & Prov. Eng.] [1913 Webster] Has he not well provided for the bairn? --Beau. & Fl. [1913 Webster]WordNet (r) 3.0 (2006):
bairn n 1: a child: son or daughter