Microampere
One millionth of an ampere. 

Microcomputer
Personal computer operated with a microprocessor. 

Micrometer
U-shaped frame with a spindle with 40 threads per inch, which is able to measure, with precision up to the nearest 0.001 of an inch. Each time the spindle revolves, it moves it 1/40 (.025) of an inch. The thimble, which encloses the spindle, has 25 equally spaced graduations, around it. When the thimble revolves 1/25 of a revolution, the spindle moves 1/1000 of an inch. 

Microstructure
Structure of a material or cell, as seen through a microscope, such as the crystalline structure of metal. 

Mildew
Any fungus that attacks various plants or appears on a material when exposed to dampness, which results in a thin, furry, whitish discoloration.

Mild Steel 
Steel used to produce structural beams and brackets, nails, etc. due to its low carbon content and lack of special alloying elements. 

Mildeweide 
Chemicals which are poisons, added to coatings such as paint, so that it retards the growth of mildew by killing it on contact. 

Mile, Nautical 
Linear measurement equal to 6,080 feet, which is used to denote international sea and air distances. 

Mile, Statute
Linear measurement equal to 1,760 yards or 5,280 feet, which is the common measurement of U.S. linear surface. 

Milestone 
1. A significant or important event. 
2. Pillar set up to denote the distance in miles to or from a certain place.

Mill 
1. One tenth of a cent. Used in expressing tax rates on a per-dollar basis of assessed valuation. 
2. A building with machinery for manufacturing or processing something. 
3. To grind, work, process or shape a material.

Mill File
File, formerly used for sharpening lumber mill saw teeth, which can be used to smooth, shape and sharpen metal. 

Mill Glaze 
Shiny spots created on wood by the action of saws, when wood is cut at a mill. 

Millage Rate 
Tax rate applied to property. Each mill represents $1 of tax assessment per $1,000 of assessed property value. 

Milled-each-end Pipe 
Asbestos cement pipe sections whose ends have been milled, providing a smooth, exterior surface for joints. 

Milled-overall Pipe 
Asbestos cement pipe whose surface has been completely milled, providing a smooth, exterior surface so that it can be cut and joined at any length, not needing additional milling. 

Milli 
Prefix that denotes 0.001. 

Milligram 
Metric measurement denoting 1/1000 of a gram. 

Millimeter 
0.039 U.S. inches or 1/1000 of a meter. 

Milling Cutters 
Tool available in a variety of shapes, normally with hardened steel or carbide-tipped cutting wheels, used to shape materials such as gear wheel or to make cuts. A milling machine keeps the work in the exact spot needed for the rotating cutters to work accurately. 

Milling Machine 
Machine, which combines a holding and moving apparatus for material as well as the cutters to accurately shape it. 

Millwork 
Moldings, jambs, etc which are formed into their finished shapes by removal of excess material.