Meaning: This idiom is used to describe a completely separate or unrelated issue or topic that differs significantly from the one being discussed. It implies a shift in focus or a change in subject to something distinct or unrelated.

Usage in Example Sentences:

1. “We were discussing the budget, but now you’re talking about marketing strategies— that’s a horse of a different color.”
2. “I thought we were discussing vacation plans, but now you’re bringing up work-related issues; it’s like talking about a horse of a different color.”
3. “The initial proposal was about improving infrastructure, but now you’re proposing changes to healthcare— that’s a horse of a different color altogether.”

Origin: The origin of the idiom “horse of a different color” is traced back to Shakespeare’s play “Twelfth Night,” written in the early 17th century. In the play, the character Feste uses the phrase in a metaphorical sense to refer to a situation that is different or distinct from the one previously mentioned. Over time, the idiom evolved into a common expression used to describe a shift in focus or a change in topic to something unrelated.