Crossword

"7 across, 2 letters", I said to my Geordie mate as we were doing a crossword together,
"What's the clue?", he asked
"25th and 9th letters of the alphabet" I said, "Do you know it?"
"What's the clue?", he asked
"25th and 9th letters of the alphabet" I said, "Do you know it?"
Spoiler: