Frances McDormand single-handedly brought down the house with her acceptance speech during the 90th Academy Awards.

The 60-year-old star took home the Best Actress Oscar for her role in Three Billboards Outside Ebbing, Missouri, for her career-defining performance as a vengeance-seeking mother that takes on the authorities after her daughter is raped and murdered.

Rather than the customary 'thank yous', she used her platform to make a passionate plea for greater equality in film.

In one of the most powerful moments of the night, she asked every nominated woman in the crowd to stand up and be recognised.

"Look around, ladies and gentlemen, because we all have stories to tell and projects we need to be financed," she told the star-studded crowd.

"Don't talk to us about it at the parties tonight - invite us into your office in a couple of days, or you can come to ours, whatever suits you best - and we'll tell you all about them."

She closed her speech with the words: "I have two words to leave you with tonight - inclusion rider."

Within minutes the internet was on fire with searches for the phrase and questions like "what is inclusion rider?" from inquisitive minds.

So what is the meaning of the term that McDormand left with her fellow thespians?

An inclusion rider is a clause that actors can put in their contracts that requires the cast and crew be diverse in order to retain the actor.

The concept was explored in a TED talk in 2016 by Stacy Smith, founder of the Annenberg Inclusion Initiative at the University of Southern California. She suggests that an "equity clause" or an "inclusion rider" could help combat the lack of diversity in the film industry.

"We're not going back," McDormand said in the winners' room. "This whole idea of women trending? No. No trending. African Americans trending? No. No trending. It changes now, and I think the inclusion rider will have something to do with that."

McDormand's comments come on the heels of Time's Up – an initiative which also aims to combat gender inequality and sexual harassment in the workplace, which has dominated award season.

Just as with the #MeToo movement, it was launched in the wake of the Harvey Weinstein sex scandal which cast a spotlight on Hollywood's seedy underbelly.