Definition of "tournedos"

‘Now,’ he turned back to the menu, ‘I myself will accompany Mademoiselle with the caviar, but then I would like a very small tournedos, underdone, with sauce Béarnaise and a cœur d’artichaut. […] ’

1953, Ian Fleming, chapter 8, in Casino Royale, page 47

He loves grilled chops, sole meunière, rare tournedos and fresh vegetables.

2007 January 19, Elaine Sciolino, “The French Know Where 007 Acquired His Savoir-Faire”, in New York Times‎