Every day's a school day, isn't it?

Just recently, people only just realised the meaning behind ABBA's name – 50 years after their Eurovision win. Many made the discovery after "rare" footage of the four emerged online.

A video was shared on TikTok which showed members of the pop band discussing how the name came about. It turns out ABBA is an acronym which uses all their names. For example, band member Anni-Frid who is the last "A".

Now a new revelation has been revealed on X, formerly Twitter, by the Today Years Old account which boasts 1million followers. The account unveiled an image showing why 1st, 2nd and 3rd are spelt the way they are.

The tweet showed a photo which read: "How old were you when you realised that the 'st' in 1st, the 'nd' in 2nd and the 'rd' in 3rd is because it's the last two letters of the numbers in the words."

Are your minds reeling yet? Ours sure are...

The post, which hit the internet earlier this month, has since racked up a whopping 273,700 views and 1,400 likes. Reactions varied, with one person confessing: "Today. Never thought of it."

Another quizzed: "Really?" While a third added: "It's so simple! How did I not know this?" And a fourth chimed in with: "Just now."

Meanwhile a fifth simply dropped the mind-blown emoji. But not everyone was taken by surprise.

One X user boasted: "Ummmm I've known that since I was a kid."

Another social media user expressed concern: "I'm worried about y'all."

If this nugget of knowledge is news to you, leave us a comment in the section below...

In other mind-blowing news, people are only just realising the "correct" way to put a top sheet on a bed.

The conversation was sparked by a woman's Facebook query regarding how others make their beds, following a visit from her mother-in-law.