Idiom:

Pearl of wisdom ( truth )

Hit the book:

Private label

Oversize

Bulk

Warehouse club

Awkward

Practical purpose

Bargain

Bottom shelf

What's there: Store and private-label brands; oversize and bulk items.

Why: "Store brands go on shelves four and five because people who buy store brands will always hunt for them," says Childress. "Thesupermarkets carry bulk items to compete with warehouse clubs like Sam's and Costco," Liebmann explains, and bulk items are awkward to store anyplace but the bottom shelf.