heyo exclamation2 •hey; hallo; a casual greeting'Heyo!' he said to himself. 'What's all this going on? Just wait a minute, and I'll find out!' — 1948 •hey; hello; a casual greeting.“Heyo!” He heard a call from the edge of the bluffs and turned to see Jake Simmons angling across the clearing to intercept him. “Hold up a minute, Joe,” Jake called after him. — 2009
