Cilly can refer to:
*an alternative spelling of
Celje
Celje (, , ) is the List of cities and towns in Slovenia, third-largest city in Slovenia. It is a regional center of the traditional Slovenian region of Styria (Slovenia), Styria and the administrative seat of the City Municipality of Celje. Th ...
, the third largest city in Slovenia
*
Cilly, Aisne, a commune of the Aisne ''département'' in northern France
*
Cilly Aussem
Cilly Aussem (; 4 January 1909 – 22 March 1963) was a German tennis player.
She was the first German, male or female, to win the singles title at Wimbledon, which she did in 1931. She also won the women's single titles at the French Champions ...
(1909–1963), German female tennis player
*operator sloppiness when enciphering messages, which helped with
cryptanalysis of the Enigma
Cryptanalysis of the Enigma ciphering system enabled the western Allies of World War II, Allies in World War II to read substantial amounts of Morse code, Morse-coded radio communications of the Axis powers that had been enciphered using Enigm ...
{{disambiguation