- main operation
- main pulley
- main shaft
- main stairs
- main station
- main vent
- maintenance building
- maintenance chart
- maintenance cost
- maintenance enterprise
- maintenance gang
- maintenance illuminance
- maintenance management
- maintenance painting
- maintenance point
- maintenance shop
- maintenance station
- maintenance time
- maitenance management
- makeup pump
- macadam base
- macadam pavement
- macadam road
- macaroni tubing
- machine cipher
- machine cycle
- machine dictionary
- machine drawing
- machine excavation
- machine finish
- machine operator
- machine screw
- machine shift
- machine time
- machine welding
- macro
- macro menu
- macro sheet
- macro-assembler
- macroclimate
- macroporous soil
- made ground
- magnesia brick
- magnesia expansion
- magnesian lime
- magnesite refractory
- magnesium chlorite
- magnesium oxide
- magnetic blow
- magnetic board
- magnetic classifier
- magnetic hysteresis
- magnified moment
- main
- main box
- main court
- main drain
- main entrance
- main kitchen
- main leaf
- main line
- main program
- main reinforcement
- main route
- main shift
- main taxiway
- main tower
- main walls
- mainframe computer
- maintainer
- maintenance notices
- maintenance priorities
- maintenance team
- maintenance workshop
- major span
- makeup
- malaxator
- mallet
- malm brick
- mammock
- management contract
- management study
- management team
- managing editor
- mandrel tool
- manganese metal
- manhole cover
- manilla rope
- manipulated soil
- magnetic logging
- magnetic test
- magnetostriction drilling
- mail duct
- main bar
- main boom
- main chart
- main cornice
- main curve
- main heater
- main rail