forty-ninth parallel 
The parallel of latitude 49° north of the equator, especially as forming the boundary between Canada and the US west of the Lake of the Woods.
- cleft lip
- cleft palate
- cleft sentence
- cleg
- Clegg, Nick
- Cleisthenes
- cleistogamous
- cleistogamy
- clematis
- Clemenceau, Georges
- clemency
- Clemens, Roger
- Clemens, Samuel Langhorne
- clement
- Clemente, Roberto
- clementine
- Clement of Alexandria, St
- Clement, St
- Clemson
- clenbuterol
- clench
- cleome
- cleopatra
- Cleopatra's Needles
- Cleopatra VII