To ask about the size of an object.
From a 1950's TV show entitled "What's My Line?
On that long-lived program, the panelists tried to determine the occupation of a guest. This often involved guessing at the nature of a product with which the guests might be identified and, to that end, finding out the size of the product. The commonest question along this interrogative route, heard so often that it became a running gag, was "Is it bigger than a breadbox?"