underway /ˈʌndə(ɹ)weɪ/noun 3/ʌndəɹˈweɪ/ adverb 1forms 3 noun3 •A road, track, path, or street for going under another way or obstacle; an underpass.As Minneapolis grew, the city demanded that M&StL construct "underways" beneath city roadways. — 2005 •An underground passage, subway, tunnel.There are in fact many such subterranean underways in Germany, speeding traffic beneath bergs, burgs and villages and into and around and under big city downtowns ... — 2004 •A voyage, especially underwater.I had been the diving officer on three previous submarines, …, and was an experienced officer of the deck with many underways and landings under my belt on all three. — 2008 underway UK /ʌndəˈweɪ/US /ʌndəɹˈweɪ/ adverb1 •In motion, in progress; being done or carried out; on a journey.The next wave, well underway, is shipping back-office business tasks overseas, ... — 2008 formsunderways · more underway · most underway