Arsenal F.C. is known as "The Gunners" because the team was founded in a place associated with the military. Thus, the team's logo features a cannon, and the team's nickname reflects that influence as well.
Arsenal F.C. was founded in 1886 in Woolwich, a district in southeast London, England. At the time of the club's founding, the Royal Arsenal, Royal Artillery Regiment and various military hospitals that still exist today were all present in Woolwich. The team's crest, unveiled in 1888, originally featured three cannons. In 1922, it was changed to show only one cannon, consistent with the team's nickname, "The Gunners."