explanation needed - what is a Rep Tie?

I have always understood that a 'rep tie' is a necktie that has certain colored stripes that correspond to certain schools, or school colors...something of that sort.

In the story I'm writing, I have a line I'd like to use and I wanted to make sure that I could reference the phrase 'rep tie' but now that I google it, and Wiki it, I find no mention anywhere.

I KNOW that I've read it somewhere before...can someone help me out? I know I'm not crazy, and did not make this up!

I think it's something like 'the old school tie' ex. Harry Potter series: Hogwarts has 4 sections, each designated by two colors.

got this too:

The Striped Rep Tie
Let's get the nomenclature straight: when striped rep neckwear is discussed, the "rep" refers to the weave in the silk fabric, not to the repetitive pattern of the stripes. Most silk neckwear is produced in only a few weaves: rep (with longitudinal ribs), ottoman (with crosswise ribs), crepe (with a broad range of grained surface effects) and faille (with conspicuous crosswise ribs).

The necktie, of course, has a long history. Roman soldiers apparently wore cloths tied around their necks as protection from the sun, the cold and perhaps the odd sword swipe. The English word cravat is a corruption of the French word for Croatian, and came to be associated with neckwear because Louis XIV employed a troop of Croatian mercenaries who were fond of wearing colored ribbons around their necks. Then there was George "Beau" Brummell, who made his way up in society by dint of his wit and manners, the impeccable cut of his suits and fresh linen, and his ability to tie the most elegant neckband in London. It's not known whether Brummell wore striped neckwear, but in a self-portrait of a dandy named Ferdinand Georg Waldmuller done in 1828--the Beau had fled England a dozen years earlier and was then living in poverty in Calais--the artist is wearing white-and-blue striped neckwear. The American interest in the genre may well date from 1919, when the Duke of Windsor (then Prince of Wales) made his first visit to the United States. Fashion spotters were quick to report on everything he wore, and he was fond of displaying his regimental tie of broad blue-and-red stripes. (He was a former officer of the Grenadier Guards.) The Duke wrote amusingly of some confusion concerning the origins of that particular tie in his book Windsor Revisited:

Once in Washington, a reporter caught up with me and asked me what tie I was wearing. I replied: "The Guard's tie." Not seeming to understand me correctly, he repeated the question. "What kind of a tie?" I answered him again: "The Guard's tie." Misunderstanding my pronunciation he settled for "Gawd's tie." Afterwards he wrote in his column that I had "left this reporter doubtful as to whether the Almighty had actually ever devised a tie of his own."

Striped ties became collegiate favorites (whether they were regimental, club or college colors) in the years immediately following the First World War and have remained so ever since. The Robert Talbott Co. of Carmel, California, is the only U.S. manufacturer that regularly stocks a complete list of "Old School" college rep striped ties. The Ben Silver Collection, a catalogue of fine neckties in Charleston, South Carolina, lists a plethora of rep neckwear woven in England.