The Collaborative International Dictionary of English v.0.48:
Breadthwise \Breadth"wise\ (br[e^]dth"w[-i]z), ads. In the direction of the breadth. [1913 Webster]WordNet (r) 3.0 (2006):
breadthwise adv 1: in the direction of the breadth; "cut the cloth breadthwise" [syn: breadthwise, breadthways, broadwise]