Welcome aboard, Press_Run.
I do seem to recall maybe one or two PCE games that did say START instead of RUN. I couldn't get past the title screen of those games.
City Hunter and Hihou Densetsu: Chris no Bouken use START, though they couple it with PUSH rather than PRESS.
I hope Insert_Coin, Game_Over and High_Score will join our party in brief as well.
How about GET_TRY (Aldynes) or BEGIN
2ING (Burai)?