What does "a penny for your thoughts" mean?

A polite, curious way of asking "what are you thinking?" - typically when someone seems lost in thought or quiet.

"You've been silent for a while - a penny for your thoughts."
"A penny for your thoughts?" (said when someone looks pensive or distracted)

When someone is noticeably quiet, daydreaming, or visibly preoccupied. It's an invitation to share their thoughts without demanding it.

Slightly old-fashioned but still understood and used, particularly by older speakers. In modern casual conversation, people are more likely to say "What are you thinking?" or "You okay?" - but a penny for your thoughts is a charming, more poetic alternative.

One of the oldest English idioms - attributed to Sir Thomas More in the 1500s. The penny has long since lost its value, but the phrase survives. The coin image suggests the thought has worth - you'd pay to know it.

• "What are you thinking?" - direct
• "Penny for your thoughts?" - shortened version
• "You seem miles away." - observing the distraction
• "What's on your mind?" - casual, friendly