- cloning technology
- cloning vector
- clonorchiasis sinensis
- clopen
- clopen algebra
- clopen set
- clopyralid
- cloransulam-methyl
- Clorinda Matto de Turner
- closable manifold
- closable operator
- closable positive definite form
- close
- closeable operator
- close arc
- close binary
- close binary galaxy
- close binary star
- close binary system
- close collision
- close configuration
- close-confinement
- close coupling approximation
- close-coupling approximation
- close coupling calculation