the thing

noun

1

: the item that is the most fashionable or popular

Long skirts are the thing to wear this season.

It's the newest/latest thing in fashion.

2

: the fashionable or proper way of behaving, talking, or dressing

It's the thing this year to buy products made from recycled materials.

3

: the reason for something

OK, here's the thing: I don't have enough money to go to college.

I'm sorry I didn't call you. The thing is, I've been really busy with work and school.