The story
From flag + pole. Cognate with West Frisian flaggepeal (“flagpole”), Dutch vlaggenpaal (“flagpole”), Low German Flaggenpohl (“flagpole”), German Flaggenpfahl (“flagpole”). Compare also West Frisian flaggemast (“flagpole”, literally “flag-mast”), Dutch vlaggenmast (“flagpole”, literally “flag-mast”), Low German Flaggstock (“flagpole”, literally “flag-stick”), Danish flagstang (“flagpole”, literally “flag-pole”), Swedish flaggstång (“flagpole”, literally “flag-pole”), Norwegian flaggstang (“flagpole”, literally “flag-pole”), Faroese flaggstong (“flagpole”, literally “flag-pole”).
Etymology from Wiktionary, CC BY-SA 4.0.