That's not really the concept. People know what an orca is.
But if you see a crossword clue that says "black and white animal", you know that the answer is ORCA without even needing to look at the number of letters in the answer. (Could it be "skunk"? Could it be "panda"? No, those are stupid questions.) Same thing if the clue is "marine predator". (Could that be "shark"? No.) The words I listed are incredibly likely to appear in crossword puzzles. That's what's weird about them.
That's not really the concept. People know what an orca is.
But if you see a crossword clue that says "black and white animal", you know that the answer is ORCA without even needing to look at the number of letters in the answer. (Could it be "skunk"? Could it be "panda"? No, those are stupid questions.) Same thing if the clue is "marine predator". (Could that be "shark"? No.) The words I listed are incredibly likely to appear in crossword puzzles. That's what's weird about them.