Bae is an acronym, supposedly: "before anyone else." That backronym became popular around 2014, but the word itself is older. It may come from the Danish word for poop, or from a shortening of "baby." In African American Vernacular English, "bae" has been used for years to mean a romantic partner. Then Twitter got hold of it. Suddenly everyone was calling their boyfriend or girlfriend bae.

The word is affectionate but not intense. "Bae" is lighter than "soulmate" and more casual than "partner." It can also describe a favorite thing: "Pizza is bae." That use is playful and hyperbolic. It is not literal romance. It is just strong affection, the same way you might say "I love this song."

Related slang

• Boo: similar, slightly older.
• Hubby: husband, affectionate.
• Wifey: wife or girlfriend, affectionate.
• Partner: gender-neutral, serious.

Like all slang, bae peaked and faded. It was mocked, memed, and overused. Some people still use it. Others cringe. That is the lifecycle of internet words. They arrive fast, spread faster, and leave a residue. Bae left a residue in dictionaries. It is official now, even if it sounds dated.