Meme-stock mania might be back, but old heads may have noticed that the moves this time around are lacking a certain explosiveness.

By now most people, even those vaguely tuned into finances, have heard the phrase "meme stock." But if you're just catching up, here are some basics.

Meme stocks are back. Jolted by a sudden surge in Opendoor stock last week, a handful of other shares have ripped higher on interest from retail traders.

Shares in Krispy Kreme donuts, camera maker GoPro, and retailer Kohl's have risen dramatically this week, driven by online hype.

Sydney Sweeney’s new American Eagle campaign is sending more than just hearts racing. The 27-year old “Euphoria” actress threw markets into a frenzy on Wednesday night when her collaboration with the clothing brand catapulted the company’s stock during after-hours trading.