Pronunciation: (flag'ship"),[key] —n. 1. a ship carrying the flag officer or the commander of a fleet, squadron, or the like, and displaying the officer's flag.
2. the main vessel of a shipping line.
3. any of the best or largest ships or airplanes operated by a passenger line.
4. the best or most important one of a group or system: This store is the flagship of our retail chain.