The first completed forward pass in professional football came in 1906, when Massillon (Ohio) Tigers quarterback George Parratt, who was known as Peggy, threw to an end named Bullet Dan Riley. There were no reports of any disputes over whether it really was a catch.

Since then, there have been hundreds of thousands of catches in professional football, and many times more than that at other levels. Just in the past 50 years, since the 1966 season that ended with what is now called Super Bowl I, there have been 392,218 completed regular-season passes in the NFL.

And yet it has never been more difficult to understand what constitutes a catch in football than it is today.

It is possible that “Was that a catch?” has replaced “Are you ready for some football?” as the most-asked question raised by NFL fans on fall and winter Sundays.

Every week, it seems, at least one crucial catch/no-catch is scrutinized, video reviewed and debated. Some rulings defy logic, if not physics. Most reverse a game’s momentum and some flip its outcome. All get some portion of the football populace — fans, players, coaches, commentators — second-guessing their own ability to know just what a catch is.

So, with Super Bowl 50 approaching in Santa Clara, Calif., the biggest worry for those who care about football is not just whether 39-year-old Denver quarterback Peyton Manning (6,125 of those completions) can win another Super Bowl, or if Cam Newton (1,440 completions) can bring a first championship to Carolina, or whether El Niño will turn the whole event into a soggy scrum.

It is whether the game will be decided on yet another catch/no-catch controversy. The constant bickering over how to define a catch has gotten so noisy that Roger Goodell, the NFL commissioner, has convened a committee to settle on new language for the rule book that will put the issue to rest — or at least give everyone new material to argue about.

Never in the game’s history has there been so much debate over something seemingly so simple.

The debates over the “process of the catch,” an obtuse phrase the NFL employs, ignited in 2010, when Detroit’s Calvin Johnson caught an apparent game-winning touchdown pass over a Chicago Bears defender, took two steps in the end zone, spun as he moved the ball from both hands to his right hand, fell down on his empty left hand and then let the ball out of his right hand as it touched the turf so that he could jump up and celebrate.

After some confusion, the referee announced that it was not a touchdown.

“The ruling on the field is that the runner did not complete the catch during the process of the catch,” the referee announced, which was football-speak for “let’s all go crazy on talk radio this week.”

The NFL tinkered with the rule — often called the Calvin Johnson rule — and has tinkered some more, mostly adding language that only lawyers could love. It did nothing to stem the controversies.

During last season’s playoffs, Dallas’ Dez Bryant made a leaping grab against the Green Bay Packers, took a couple of steps, and reached for the goal line as he fell. The ball was jarred loose. The pass was deemed incomplete. Head scratching and verbal mayhem ensued.

The NFL did not change the rule last offseason, but attempted to clarify it, in a way that wipers clarify a windshield covered in mud by smearing the mess from side to side.

Long ago, officials were asked simply to judge possession of the ball — the dictionary definition of catch, plus two feet on the ground. Now they must ascertain the actions of the entire rest of the body, if not the mind.

Officials are now asked to decipher whether the player has shown enough after taking possession (but before it can be ruled a “catch”) to be classified as a runner (leading to one set of rules), or whether the player took possession while falling (leading to another).

How does a receiver prove he is a runner? Good question.

“He does that by gaining control of the ball, touching both feet down and then, after the second foot is down, having the ball long enough to clearly become a runner, which is defined as the ability to ward off or protect himself from impending contact,” the NFL said in its offseason attempt to help people — including, presumably, on-field officials and the league’s own employees on Park Avenue — understand.

In other words, rather than judging whether a receiver caught a ball, officials now judge whether he caught the ball and became a runner, which might just be the more subjective of the two acts.

If the receiver is not a runner, he might be a faller, which leads to an entirely different rule.

“A player is considered to be going to the ground if he does not remain upright long enough to demonstrate that he is clearly a runner,” is how a former NFL vice president for officiating, Mike Pereira, explained it last summer.

Is that helpful? Generally, if the player is falling, he better not let go of the ball until sometime after he has come to a complete stop. From the NFL’s attempt to clarify:

“If, before becoming a runner, a receiver falls to the ground in an attempt to make a catch, he must maintain control of the ball after contacting the ground. If he loses control of the ball after contacting the ground and the ball touches the ground before he regains control, the pass is incomplete. Reaching the ball out before becoming a runner will not trump the requirement to hold on to the ball when you land. When you are attempting to complete a catch, you must put the ball away or protect the ball so it does not come loose.”

This interpretation is simple to understand and impossible not to mock. When Oakland’s Michael Crabtree caught a pass along the sideline this season, he landed with both feet in bounds, got shoved from behind, tucked the ball under an arm, stumbled several steps out of bounds — doing everything but taking out cheerleaders and water jugs along the way — and lost control of the ball once he put his hands on the ground to break his fall.

By the “100 drunks in a bar” standard promoted by the football commentator Mike Florio, it was a catch. By the NFL’s standard, it was not. It raises the idea that replay reviews might best be performed by people in a bar, perhaps in a neutral city, each given a “yes” or “no” button to push.

Why is it so complicated? “To use your hands to stop and hold an object that is moving through the air,” is how Merriam-Webster neatly defines the verb, among other interpretations. “To seize and keep hold of” is one way that the Oxford English Dictionary explains it.

We catch fish, colds, thieves, breaks, waves and fire. We catch rides, flights, buses, trains. We catch rising stars and falling ones, to put in our pockets. We catch someone’s eye, hoping they catch on and consider you quite the catch. We catch people in the act. We get ourselves in a Catch-22.

We have catchers, which seems like as good a name as receiver but was already taken. There is “Catcher in the Rye” and the catch of the day.

No one disputed The Catch in football (Dwight Clark) or The Catch in baseball (Willie Mays). Shonda Rhimes is making “The Catch” for television.

Generally, the confusion over a catch in the NFL is a symptom of instant replay, where a plain eyeball test will not suffice. Where once the catch was football’s version of obscenity — we know it when we see it — it became a play to be dissected from all angles and the slowest possible speeds.

Scrutiny invites doubt. It is like staring at a word — say, “catch” — for so long that it no longer looks right. Catch? Catch? Wait. Ketch?

Goodell promises to take another look at the catch rules this offseason “to find a better solution, if it’s out there,” he said.

There is just one game remaining before that solution — if it’s out there — is found. It just happens to be the Super Bowl, the 50th one, which seems quite a weird time to be asking, “Was that a catch?”