- clean timber
- clean water
- cleaner jig
- cleaning material
- cleaning out
- cleansing
- clear area
- clear day
- clear etching
- clear space
- clear spot
- clear varnish
- clearance area
- clearance gauge
- clearance hole
- clearance lamps
- clearance space
- cleared
- clearing
- clearing office
- clearway
- cleavable
- cleavage crack
- cleavage fracture
- cleavage strength
- cleave
- cleave fracture
- cleaving
- cleaving timber
- cleft
- cleft water
- cleft weld
- clench
- clerestory
- clerical machine
- clerical staff
- clever
- click
- click spring
- click wheel
- clicking
- clicks
- client
- client application
- climate
- climate zone
- climatic
- climatic anomaly
- climatic conditions
- climatic map
- climatic region
- climatic test
- climatic year
- climatology
- climax
- climb
- climb cruise
- climbing
- climbing ability
- climbing forms
- clinch bolt
- clincher
- cling
- clinker brick
- clinograph
- clinometer
- clinostatism
- clip
- clip curve
- Clip Gallery
- clip hooks
- clip tack
- clipper
- clipper circuit
- clipping
- clipping level
- clipping path
- clivus
- clock cycle
- clock drive
- clock frequency
- clock pulse
- clock register
- clock relay
- clock speed
- clocking
- clog
- clogged head
- cloister
- clonotomy
- close
- close fold
- close fractionation
- closure
- closure dam
- closure embankment
- closure flow
- closure function
- closure valve
- clot