- coalescer
- coalescing agent
- coalification
- coalite
- coarse adjustment
- coarse aggregate
- coarse cement
- coarse component
- coarse emery
- coarse grain
- coarse lattice
- coarse porosity
- coarse suspension
- coarse-grained
- coastal area
- coastal deposit
- coastal facies
- coastal lake
- coastal tanker
- coastward
- coated fabric
- coating
- coating index
- coating material
- cobalt
- cobalt bloom
- cobalt blue
- cobalt catalyst
- cobalt glance
- cobalt naphthenate
- cobalt ore
- cobaltammine
- cobaltiferous
- cobbing
- cobble wax
- Coblentzian stage
- clinker
- clinkering
- clinkering coal
- clino-unconformity
- cllisite
- clod
- clogged
- clogging
- close foliation
- close investigation
- close joint
- close nipple
- closed basin
- closed cell
- closed coil
- closed diaphragm
- closed heater
- closed mold
- closed structure
- closed tester
- cockade ore
- cockade structure
- cocoa
- cocobola
- coconut oil
- code
- codeine
- codeposition
- codliver oil
- cogger
- cohade
- coherent boundary
- coherent particle
- cohesion moisture
- cohesiveness
- cohobate
- coir rope
- coke button
- coke chamber
- coke drum
- coke formation
- coke number
- coke pig
- coke residue
- coke test
- coke tower
- coking
- coking power
- coking process
- coking time
- coking value
- colchicine
- cold area
- cold break
- cold cure
- cold decomposition
- cold pressing
- cold reflux
- cold rubber
- cold setting
- cold steam
- cold tarring
- cold-settling
- collagen