Dic: on the side

• He makes a little money on the side by cleaning windows in his spare time.
• I think he has another woman on the side (=a relationship with a woman who is not his wife).
• I'd like a salad with the dressing on the side (= with the dressing served separately from the salad), please.
• I'll have a omelette with fries on the side, please.

* * *

△ in addition to your main job.
△ secretly.
△ [mainly US] (of food in a restaurant) served on another plate, or not on part of the meal.

... CALD