The Collaborative International Dictionary of English v.0.48:
Edgeways \Edge"ways\, Edgewise \Edge"wise\, adv.
With the edge towards anything; in the direction of the edge.
[1913 Webster]
to get a word in edgewise to succeed in expressing an
opinion in a conversation, in spite of constant speech
from another or others; as, he talked incessantly and I
couldn't get a word in edgewise.
Note: the form edgeways is now uncommon.
[PJC]
Glad to get in a word, as they say, edgeways.
--Sir W.
Scott.
[1913 Webster]