The Merriam-Webster online dictionary defines the word "anachronism" as "a person or a thing that is chronologically out of place." In MMA, the term "ground-and-pound" fits that bill. 

Observers coined this term back in the sport's Iron Age to describe the act of hitting an opponent while you're controlling them on the mat. That's it. It's just that simple. It's so simple, in fact, that it can be hard to conceive of a time when that action would even require its own term. Using the term now is a little like watching a head kick and calling it a "kickboxing-style strike."

But this is exactly what makes Khabib Nurmagomedov so remarkable. He's so good with this phase of the game that he has managed to reinvent it—taking us all back to a time when ground-and-pound felt like something fresh.

So while the term may be anachronistic, Nurmagomedov's new spin has turned them to into a new concept entirely. It's why he's not just the UFC lightweight champion but also a popular choice as the best fighter in the world right now at any weight class.

On Saturday in the main event of UFC 254, Nurmagomedov puts his lineal title and flawless 28-0 record on the line against interim titleholder Justin Gaethje (22-2). The American is known as a knockout artist whose body will only touch the canvas if his opponent insists. Nurmagomedov will insist. If he manages to do it like he's done it to all his previous opponents, Nurmagomedov's brutal ground attack will give Gaethje and fans a new definition of deep water.

The History of the Hammer

Any UFC fan worth their salt will remember that the whole enterprise began as a showcase for Brazilian jiu-jitsu, the martial art pioneered by the Gracie family, with Royce Gracie serving as its champion and ambassador in the cage. The original concept was to pit BJJ against what were then the more familiar fighting styles—e.g., karate, boxing and the like.

Wrestling was in the equation but not at the same level. Dan Severn was the first real wrestler to make hay in this newfangled sport. A two-time All-American at Arizona State, Severn crossed over to the Octagon in 1994 and made a run to the UFC 4 tournament finals, when he was submitted by Gracie.

Fellow wrestler Ken Shamrock faced Gracie at UFC 5, grinding Gracie to a draw after 36 agonizingly boring minutes. It was like watching paint dry, only it was lead paint, so you felt mildly and somehow indelibly intoxicated by the drudgery.

Shamrock's performance that night was Severn-style. Outside of the occasional suplex, The Beast relied on smothering his opponents in top control and simply waiting things out—keep in mind that there were no time limits in the early days. Palm strikes and basic submissions were part of the blueprint, and moments of violence were possible (like Severn's gory knee-drop TKO of Oleg Taktarov in the UFC 5 semis). But by and large the Severn plan was a very conservative one.

While wrestlers continued to migrate to MMA—it remains arguably the most effective skill base a fighter can have—they didn't always light the world on fire.

Did someone say fire? In 1996, a wrestler by the name of Mark "The Hammer" Coleman took things to a new level, taking full advantage of the UFC's rather permissive rule set to brutalize opponents and set the fanbase ablaze. Rather than impose his wrestling will and wait like a buried flounder for offensive opportunities to present themselves, Coleman used the takedown as a means to an end. In this case, "end" applies to his opponents, who lay helplessly as Coleman battered them with punches, hammerfists, elbows and even, back then, headbutts.

Ground-and-pound was born. As Coleman himself explained to feature writer Chuck Mindenhall back in 2013:

"People don't realize that it did take some technique. You had to throw it properly, or you were going to mess yourself up. So there was technique involved, the hard part of my head into the soft spot on his face. And when he goes to block it, I have a right hand, and a left hand.

"I wasn't great at math, but…it kind of made sense to me. It seemed a little bit not fair. There was always something open. The rib, the face, or the headbutt. He couldn't block all three. UFC 10 was the right time for me, before everybody caught up."

Into the Modern Era

Coleman rode this style to great success, including the 2000 Open-Weight Grand Prix Tournament championship in Japan's Pride FC promotion—arguably the sport's most prestigious prize at the time.

As with all evolutionary steps, the fighting world did indeed catch up. Tito Ortiz made it the cornerstone of a UFC run that turned him into a champion and an early antihero of the sport. It made Matt Hughes a multi-time champion in the welterweight division.

Although Georges St-Pierre and Fedor Emelianenko were not amateur wrestlers by background, the strategy was central to their careers, both of which put them on almost everyone's Mount Rushmore of the greatest competitors in MMA history.

The list goes on. It's so common that it's hard to picture a wrestler (or even any ground sequence at all) that does not contain at least some kind of striking-based offense.

Plenty practice the craft, but few have perfected it. Enter Nurmagomedov.

The Nurmagomedov Approach

Like Fedor and GSP, Nurmagomedov's background isn't in wrestling per se but in sambo, the Russian (and, if you'll permit a tangent, very unfortunately named) blend of hand-to-hand combat techniques used in the military, among other settings. This style emphasizes controlling an opponent's torso, hands, wrists and legs as a way of incapacitating the opponent and his defenses.

Nurmagomedov can get you down through any manner of techniques, from throws to trips, but the champ's signature move is to grab the single- or double-leg takedown and then penetrate forward to mash his opponent's back against the fence before dumping the poor sap on his backside. Nurmagomedov loves to leverage the fence whenever possible and will do what he can to get the action there.

From there, Nurmagomedov keeps hold of the other guy's legs and pinions him against the chain link. He then goes for wrist control or works his way up the opponent's body like a python devouring a rat. His transitions from phase to phase are seamless as his body sticks to the other man's like Velcro. Assuming Nurmagomedov gets into this position Saturday with Gaethje, notice how tightly he drapes himself over the opponent's frame. Once this guy gets on you, it's exceedingly difficult to get him off, not unlike undoing a peanut butter sandwich.

At that point, if you will excuse the technical parlance, Nurmagomedov grabs a wrist and tees off with his other hand, lacing punches and hammerfists through what remains of the opponent's defenses, sometimes while telling him that he's a baby and should give up, give up his back, give him his house, give him his firstborn, etc. He's as evil as he is mesmerizing, and he's the champ for a reason.

Going back to a previous analogy, like ground-and-pound, the term "K-1 level striking" became the subject of ridicule years ago because it became overused, a throwaway term attached to any fighter who employed a lot of kicks or had competed in kickboxing before transitioning to MMA. Imagine how good someone's striking would need to be today in order to resurrect that sort of description. You're talking Israel Adesanya levels there—an exceptional skill set.

That's where we are with Nurmagomedov. With so many moving parts blended into one serptentine progression, he's taken an old concept and made it seem prototypical. At UFC 254, the prototype faces another tough test in Gaethje. The interim champion will know full well what's coming, but if he's like Nurmagomedov's other 28 opponents, he will never know what hit him.