headboard - finds every item with the word 'headboard' in it.
headboard,king - finds all king-sized headboards.
headboard,king,white,wood - finds every item with all four words in the description.

Search for multiple items separated by '|':
dresser|nightstand - finds all nightstands and dressers
dresser|nightstand|projector screen - finds all dressers ,nightstands, and projector screens (note that spaces are not trimmed)

Combine features:
headboard,king|night,stand|screen,projector,100|logitech|ceiling,fan - finds all king headboards, nightstands, 100" projector screens, and ceiling fans.