No, the term knockout existed well before then, and was part of the common boxing vernacular. [FONT="]On January 3, 1881, back in Boston, Sullivan took on Jack Stewart, who was billed as the Canadian champion. [/FONT][FONT="]The local Boston Herald said, “Sullivan, it was anticipated, was going to ‘knock someone out,’ but he did not.” [/FONT][FONT="]Another local paper, the Boston Daily Globe, said of the fight that Sullivan “managed to cross counter almost every blow from Stewart, in fact, in the first round, he knocked Stewart out of time. The second and third rounds were the same, Sullivan just playing with Stewart as a cat does with a mouse.” [/FONT] Before the 1882 Ryan fight, one Sullivan supporter said that betting on John was like finding money in the street. A Chicago man said, "Sullivan will down Ryan as sure as you live. I have seen a good many fighters, and I give you my word that I have never seen a man that I considered his equal. I saw him when he knocked Dalton out in Chicago, and his blows are like those struck with a sledge-hammer. He is a terrible hitter, and I believe he will stand to the scratch just as long as the other man will." Before the March 1884 Sullivan vs. George Robinson bout, Sullivan trainer/second William Muldoon took the platform and made a speech where he said, "This affair tonight was intended to be a knockout contest with gloves. A little difficulty, however, has arisen today in regard to the gloves. I hold in my hand one of the three-ounce gloves that Sullivan used in his fights…It was intended that, the same should be used here tonight, but the authorities would not allow it…. The gloves to be used are 8-ounce – the only ones they will be allowed to fight with. The men are going to fight on their merits, and Sullivan is going to try to knock Robinson out if he can, although it might be considered a miracle for a man to do so with these gloves." [FONT="] See John L. Sullivan: The Career of the First Gloved Heavyweight Champion. [/FONT]
Oh, go ahead and spoil a good story, Mr. Bookwriter. I had a feeling regarding that, tho. My source was the NYT obituary on Sullivan dated Feb 5, 1918, claiming Madden coined the term following the Ryan bout. Obviously, it was a term going around the fancy set at the time.
1858-11-23 The New York Herald (page 1) Exhibition of the Benicia Boy and Aaron Jones in Boston. [From the Boston Herald, Nov. 22.] ... Young John Morrissey had an encounter with James Coffee. They boxed with much earnestness, and displayed considerable science. In the third or fourth round Morrissey was knocked out of time by a blow on the jugular. ...