flag, banner, standard
旗 centers on a piece of cloth used as a symbol or signal: a flag, banner, or standard that represents a group or idea.
旗 combines 方 (flag) with 其, which likely contributes the sound. The character originally depicted a banner or standard.
The left side 方 suggests a flag, and the right side 其 looks like a stand or pole. Picture a flag waving from its stand: 旗 is a flag or banner.
For キ, imagine a key flag that unlocks a treasure: key -> キ, and the flag marks the spot.
flag
national flag
red flag
flagship
standard of revolt; banner of rebellion
headquarters (on the battlefield)
Stars and Stripes (US flag)
raising an army; raising a banner
white flag; truce flag; surrender flag
standard-bearer; flag-bearer
design (on a banner); emblem (on a flag); insignia
national flag of Japan
battle flag; standard; (regimental) colours; colors; ensign
surrender flag; white flag
flagstaff; flagpole
situation; outlook
nobori; long, narrow banner attached to a pole on one side and a horizontal rod along the top
Olympic flag
(one) flag
to make a name for oneself; to achieve success