Here's what went down ... Wednesday, the "Wicked" movie uploaded to Instagram a snippet of Ariana's rendition of "Popular" in the musical movie ... slapping the lyrics over the first look of the scene.

However, the upload seemingly had one glaring error .... this according to Glinda, herself. In the comments on the Instagram post, Ariana chimed in and revealed the word "poise" in the lyric video should actually be "ploys."

She wrote ... "it’s 'ploys' !!!!!! i love you @wickedmovie 🥲🥹."

While many rallied around Ariana's response -- given the fact that she's the one who sings the song in the movie -- some were still convinced the lyric should be, "I'll teach you the proper poise when you talk to boys."

In fact, Genius, a website known for having the world's biggest collection of song lyrics, also claims the word is "poise" in the "Wicked" anthem.

It's even hard to hear if it's "poise" or "ploys" in a snippet from original Glinda Kristin Chenoweth's Broadway rendition of "Popular" ... prompting several replays of the track in the TMZ newsroom.

While we were already inclined to believe Ariana, since she even did a cover of the song with MIKA back in 2012 ... the Official "Wicked" Vocal and Piano Book also supports Ari's position, as the sheet music shows the word "ploys" -- which feels like a win for the singer.