What does the symbol on dashboard of a 2006 ford expedition that looks like little fire hydrant mean?

That symbol on your 2006 Ford Expedition's dashboard that resembles a little fire hydrant is the low coolant level warning light. It indicates that your vehicle's engine coolant is low. You should check your coolant level immediately and add coolant if necessary. If the light stays on after adding coolant, there may be a leak in the cooling system which requires professional attention.