Loyal supporters may be found near or far and Arsenal's Frimpong may figure that if he reads up on the subject
What is a fan?
I ask only because Emmanuel Frimpong, the Arsenal midfielder, has some very precise views on the issue.
"It still amazes me that you call yourself a fan," he tweeted this week to Piers Morgan, the CNN talk-show host and disillusioned Arsenal supporter.
"A fan doesn't do the things you do. The fans are the people that travel thousands of miles every week to support their team. Fans are the 60,000 people we have every Saturday. Fans don't turn their back on their team.
"Piers, you ain't a fan. You're just some big old-school bully that has too much time on Twitter. Now you go to bed and wake up early to read."
While I admire Frimpong's passion, there are serious flaws in his logic. Not to mention the slightly concerning side issue that he appears to consider reading as somehow shameful or embarrassing.
There is the issue of distance, for starters. Must one really travel thousands of miles each week to be called a fan?
I'd suggest the exact opposite is true, that a real fan supports his local team, no matter how bad they are, rather than picking a more successful one (for the benefit of younger readers, Arsenal used to be good) on the other side of the country, continent or globe. A glory hunter is a glory hunter, no matter how many air miles they clock up.
Then there is the issue of match attendance. It is preferable to attend games, of course, but is it a deal-breaker in the definition of fan?
North London is awash with veteran Arsenal supporters who packed into Highbury while Frimpong was still a twinkle in his father's eye.
Nowadays, they simply cannot afford to go to the Emirates. Arsenal are the most expensive Premier League club by some distance, with their cheapest full-season ticket costing £951 (Dh5,478), compared to £526 at Manchester United, £595 at Chelsea or £725 at Liverpool.
By Frimpong's logic, an Islington-born pensioner who cheered Arsenal through the (mainly barren) 1960s, 70s and 80s - but cannot afford to subsidise the extravagant wages of Premier League players - is a lesser "fan" than some wealthy day-tripper in a box-fresh Gunners scarf who was still supporting Manchester United until the early noughties, will be supporting Manchester City by May, and who probably thinks Arsenal are named after Monsieur Wenger.
Frimpong can say what he likes about Morgan or grumbling fans in general, but he has no right to claim ownership of the English language.
The word "fan" is short for "fanatic", which my dictionary defines as "a person whose enthusiasm for something is extreme". (Amazing the things you can discover by reading, eh, Emmanuel?)
But extreme enthusiasm for an institution, like a football club, does not have to mean extreme enthusiasm for its personnel.
This may come as a surprise to Frimpong but fans moan about players and managers all the time. Whining is our default setting. It is borne out of our extreme enthusiasm. We love the club so much we cannot stop worrying about it.
Even the fans who chant uplifting slogans during the match and applaud you off the pitch go home and moan. As a crowd, we unite in vocal support. As individuals, we discuss our creeping doubts and vent our frustration.
It is not Frimpong's fault that he does not know how real fans behave. He signed for Arsenal at age nine; he was happy in his reality-free bubble until it was penetrated by a few choice words on Twitter.
Maybe that is why he has such a downer on reading.