'Throwing in the towel' is one of the more popular idioms in the English language and an acknowledgement of early defeat.
Example: Far behind in the polls, the candidate decided to throw in the towel prior to the election.
In boxing, 'throwing in the towel' is a century-old ritual... and major misconception.
In the movie Rocky IV, Apollo's cornerman pleads with Rocky, Apollo's head trainer, to throw the towel in the ring when their fighter starts to take a savage beating. And even today, cornermen will sometimes chuck a towel in the ring as a sign of surrender, thinking the bout will automatically be stopped.
But that's not how it works.
The referee, and only the referee, can stop a fight. As a matter of fact, I've seen 'alert and judicious' referees toss the towel back into the corner and allow the fight to continue.
While the referee will sometimes choose to stop a bout based on the advice of the corner or a towel toss, he is well within his right to ignore both.
Louis vs Schmeling 2, 1938
Max Schmeling, having already tasted the canvas three times, appeared to be in dire straits against fight legend Joe Louis in their rematch prompting Max's cornerman, Max Machon, to throw a towel in the ring.
Perhaps to the surprise of some, Referee Donovan threw it back out.
After action wasn't taken following the towel toss, Machon was forced to enter the ring himself at the count of eight, at which point Donovan declared the fight over due to the condition of the felled fighter.
Cotto vs Foreman, 2010
The trainer for Yuri Foreman threw a towel into the ring in Round 8 after Foreman slipped and injured his right knee. Referee Arthur Mercante Jr, one of the best in the business, alertly threw the towel back, breaking with the so-called norm.
"I could have disqualified the corner but I don't like doing that," Mercante said.
"I saw the towel come into the ring and I threw it back. I didn't know where it came from. I didn't know who threw it in. The two fighters were in the middle of a heated exchange."
A referee may choose to stop a fight based on a plea from the ring doctor or a towel thrown in the ring but the discretion is his.
"The kid wanted to continue. He wanted to go on."
Only the referee can end a fight.
Why can't others stop the bout?
Answer: Fear of corruption. The notion is that if too many people are empowered to stop a bout, it would enhance the possibility of corruption.
As a trainer, you know your fighter better than anyone and may notice abnomalities a referee cannot spot. If you absolutely need to end a bout and throwing in the towel proves futile, enter the ring yourself a la Peter McNeeley's cormer in their fighter's bout with Mike Tyson. This will almost always result in a disqualification.