You use on the whole to indicate that what you are saying is true in general but may not be true in every case, or that you are giving a general opinion or summary of something.
1. all of something including all its component elements or parts;
"Europe considered as a whole""the whole of American literature"
2. an assemblage of parts that is regarded as a single entity;
"how big is that part compared to the whole?""the team is a unit"
Adjective
1. including all components without exception; being one unit or constituting the full amount or extent or duration; complete;
"gave his whole attention""a whole wardrobe for the tropics""the whole hog""a whole week""the baby cried the whole trip home""a whole loaf of bread"
2. (of siblings) having the same parents;
"whole brothers and sisters"
3. exhibiting or restored to vigorous good health;
"hale and hearty""whole in mind and body""a whole person again"
Adverb
1. to a complete degree or to the full or entire extent (`whole' is often used informally for `wholly');
"he was wholly convinced""entirely satisfied with the meal""it was completely different from what we expected""was completely at fault""a totally new situation""the directions were all wrong""it was not altogether her fault""an altogether new approach""a whole new idea"