How a ‘Splash’ Joke Lead to the ‘Madison’ Baby Name Boom

"Madison's not a name."

So explains Allen Bauer (Tom Hanks) to his unlikely objection of affection, a landlocked mermaid played by Daryl Hannah, as they stroll down a Manhattan sidewalk in a seminal scene from Ron Howard's beloved rom-com "Splash." Released exactly 30 years ago this Sunday, the film had an outsized cultural impact, both as a breakthrough comedy hit and the kickoff for a host of big screen careers.

But its great legacy may be a certain name that it entered forever in our lexicon.

Jennifer, Joanie, Hilary, Linda, Kim, Elizabeth, Samantha. Those were names, according to Allen.

Madison may have not been "a name" you call yourself in 1984, especially for women – it of course was in fact the last name of a U.S. president, the name of a city in Wisconsin, and most relevantly, the name of one very famous avenue in New York City.

But it's the English/human name Hannah's mythical beauty chose for herself after hearing Allen mention the street name, and in turn, led to a surge in popularity of the female baby name "Madison," a trend that quietly gained steam in the years immediately following the film's release before skyrocketing to the top of baby name lists in more recent years.

[Related: 18 Finny Facts You Didn't Know About 'The Little Mermaid']

"At the time, audiences laughed at the ridiculous choice," says Laura Wattenberg, who runs the popular site BabyNameWizard.com. "Madison was completely unheard of as a girl's name."

Joal Ryan, author of "Puffy, Xena, Quentin, Uma: And 10,000 Other Names for Your New Millennium Baby" (and Yahoo contributor), agrees: "Madison was nowhere on the radar as a girl name until 1985 -- a year after the release of 'Splash.' So, there definitely seems to be a connection there, especially since there's no other major female Madison, either real or fictional, who was out there as a role model."

And while both Wattenberg and Ryan will tell you about the power pop culture has over baby-naming conventions -- look no further than the uptick in girls named "Isabella" by mothers who love "Twilight" or boys named Espen because of the popularity of the cable network ESPN – what makes the "Splash"-Madison phenomenon unique is that, as Wattenberg points out, "its popularity was sparked by a joke."

The original Madison herself, Daryl Hannah, shares that sentiment.

The actress-turned-producer (her latest film, the anti-Keystone Pipeline documentary, "Above All Else," premieres at the SXSW Film Festival on Monday), seems to get a genuine kick out of what one of her most memorable characters inadvertently inspired.

"It's funny because no one understands the irony, because the whole point of me choosing that name was because it [was such a] silly name," Hannah tells Yahoo Movies. "Obviously everyone knew it as the name of the street. No one really saw it as a first name and that was a joke. And now, of course it's not funny at all. It's just like, Oh, what a beautiful name!' … It was funny at the time and now it's not even ironic."

According to the Social Security Administration, Madison was the 216th most popular name for girls in the U.S. in 1990, but five years later rose to 29th, and by 2000 had become number 3. It was a top-five name throughout the first eight years of the new millennium, and had only fallen to number 9 in 2012, the last year for which SSA records are available. (It is of course a unisex name as well, but doesn't rank nearly as high for boys.)

"Because it was a joke in the film, the name had a delayed takeoff," Wattenberg explains. [In the '90s], this new generation of moms had grown up with 'Splash,' so that Madison was part of their "vocabulary" of girls' names. It also helped that the name shortened to the popular girlish nickname Maddie."

Ryan says that while yes, "Splash" is owed credit for putting Madison on the map, the name itself later took on a life of its own: "More importantly people liked the sound of it. Then the last-name-as-first-name thing came into vogue. And then the snowball just kept on rolling."

[Related: 25 Signs You're a BIG Fan of Tom Hanks's 'Big']

The movie "Splash" made exactly that on the cultural zeitgeist when it was released on March 9, 1984: The film marked the first lead role appearance by TV star Hanks (beating "Bachelor Party" to theaters by three months), cemented "Blade Runner" femme fatale Hannah's status as a big-screen bombshell, featured memorable supporting turns from two "SCTV" vets (the late, great John Candy and Eugene Levy), and was the first of several box office hits for former child star-turned-director Ron Howard. With a nearly $70 million take at the box office, it was 1984's 10 highest grossing movie; it was also one of the year's most beloved.

(The hit also led to a very unfortunate made-for-TV sequel, "Splash Too," but let's all agree not to acknowledge its existence.)

Still, the greatest impact "Splash" made on our culture is arguably the thousands and thousands of Americans who have been named Madison since, either directly or later indirectly as a result of the movie.

It's fitting, then, that the film's sole Oscar nomination went to its writers, the iconic screenwriting duo Lowell Ganz and Babaloo Mandel, as well as Bruce Jay Friedman and producer Brian Grazer, who originated the story. They were the brains behind this ultimately monumental joke in the first place.

These days, Hannah says, not only does she often find herself approached by Madisons, but that she "knows lots and lots of them."

All seemingly because of a mermaid and a street sign.

To paraphrase Hanks's Allen, good thing they weren't at 149th St.

Follow Kevin Polowy on Twitter