Cryptocurrency

noun a system in which goods or services are bought and sold illegally, usually to avoid government regulations or taxes

• The government is cracking down on the black market for counterfeit goods.
• I heard you can get cheap electronics on the black market.
• Don't mess with the black market, it's too risky.
• His reputation on the black market of gossip was unmatched.

noun a person born under this sign

• The Gemini spacecraft was a manned spaceflight program in the United States during the 1960s.
• I heard that Sarah is a Gemini, just like me!
• Gemini season is the best time of year, hands down.
• Her personality is like a Gemini, constantly shifting and unpredictable.

noun P.K. is a proper noun used as a name or identifier for a person or thing.

• P.K. is a renowned physicist known for his groundbreaking research in quantum mechanics.
• I heard P.K. is giving a lecture at the conference next week.
• P.K. is a total genius when it comes to science stuff.
• In the world of academia, P.K. is like a shining star among his peers.