The phrase "bigger size" refers to something that is larger in dimensions or volume than other objects of its kind. It can be used to describe an object, person, place or thing that has a greater amount of space, length, width, height or capacity compared to others. For example, if you were referring to the physical attributes of a person, you could say they have "bigger size" meaning they are taller or heavier than average. Similarly, when describing an object such as a car, house or container, it can be said that it has "bigger size" indicating that it is larger in dimensions compared to other cars, houses or containers.