A sillcock is an outdoor water faucet that is located and attached to the exterior of a house. Sillcocks are nothing more than spigots you see coming out of your house. They essentially have a spout in which to connect hoses to or just tap water from while outside.
Sillcocks can be damaged by frost and the cold. Before cold weather comes, be sure to take the basic precautions to protect sillcocks from freezing (or you may be in for repair!). To protect from frost, disconnect any garden hoses, close indoor shutoff valves if available, and open sillcocks to drain any trapped water. You can also invest in frost free sillcocks. These special frost proof sillcocks are designed not to break in cold weather, essentially by having a water shutoff valve inside your house (warmer) to prevent any water left in the outer portion of the sill cock from freezing.