Well dictionaries don’t do phrases do they? Perhaps they do. I think I saw one once called the “Phrase Finder” and I think I may even have it. The dictionary does list it btw, as does the old standby Encarta (yes I still have mine) and it defines it as : edgewise adv adj edge first U.K. term edgeways
Now going to the book, Webster’s New World Dictionary: College Edition, pg. 460 says that the pronunciation is ej-waz. And is an adverb meaning with the edge foremost, on by, with, or toward the edge. Also as used as “get a word in edgeways, to manage to say something oneself in a conversation that is being monopolized by another or others.
meaning: Join a conversation in which another is speaking continually and leaving little opportunity for others.
‘A word in edgeways’, or as it is sometimes written ‘a word in edgewise’, is a 19th century expression that was coined in the UK. ‘Edgeways/edgewise’ just means ‘proceeding edge first’. The allusion in the phrase is to edging sideways through a crowd, seeking small gaps in which to proceed through the throng.
The phrase ‘edging forward’ exactly describes this inch-by-inch progress. It was first used in the 17th century, typically in nautical contexts and referring to slow advance by means of repeated small tacking movements, as here in Captain John Smith’s The generall historie of Virginia, New-England and the Summer Isles 1624:
After many tempests and foule weather, about the foureteenth of March we were in thirteene degrees and an halfe of Northerly latitude, where we descried a ship at hull; it being but a faire gale of wind, we edged towards her to see what she was.
This practice of ‘edging’ was used with reference to the spoken word by David Abercromby, in Art of Converse, 1683:
Without giving them so much time as to edge in a word.