closure section - command
- collect ... traffic
- collect ... train
- collecting agent
- collecting channel
- collecting container
- collecting electrode
- collecting lens
- collecting loop
- collecting main
- collecting sands
- collecting shoe
- collecting tank
- collection
- collective pitch control
- collective tolerance
- collector
- collector circuit
- collector ring
- collector shoe
- collector strip
- collector-base impedance
- collector-to-base current gain
- collergang
- collet
- collet chuck
- collet jaw
- collide
- colliding
- colliding galaxies
- colliding particles
- collier
- collimated light
- collimating cone
- collimating lens
- collimating mark
- collimating telescope
- collimation error
- collimation level
- collimator port
- collinear vectors
