6. on occasion This hall is used on great occasions, such as a big dinner, or a ball I send my best wishes on this happy occasion The weather was good except for an occasiona/ shower It snowed occasionally but not enough for skiing6.on occasion  This hall is used on great occasions, such as a big dinner, or a ball.  I send my best wishes on this happy occasion.  The weather was good except for an occasional shower.  It snowed occasionally but not enough for skiing