| Term No. | Term Name | Term Description |
| 8490 | Mac OS | A popular operating system for Macintosh computers manufactured by Apple Computer Corp...... |
| 8491 | Machine language | A language for writing instructions in a form to be executed by the machine; the language can be directly interpreted by the control section of the ma..... |
| 8492 | Macro | A combination of commands, instructions, or keystrokes which may be stored in a computer’s memory to be executed as a single command by a single key..... |
| 8493 | Macroassembler | An assembly language translator that converts macro expressions into several machine language instructions. Although macros simplify program coding an..... |
| 696 | Macroclimate | The climate over a very large areas, such as deserts or oceans...... |
| 6586 | Macroclimate | The climate representative of relatively large areas. ..... |
| 6901 | Macronutrient | An element or compound needed in relatively large quantities by an organism...... |
| 6846 | Macroorganisms | Organisms visible with the unaided eye...... |
| 7053 | Macrophyte | Large forms of vegetation...... |
| 1661 | Macrostructure | Soil structure presenting the aggregates of the mineralogical complexes into larger units, as a result of cementation...... |
| 8209 | Magnetic tape | Narrow length of thin plastic, coated with a magnetic material used to store signals magnetically...... |
| 2521 | Main body | The structural part of the dam above foundations...... |
| 4640 | Main canal, Main line, Pipe main, or Principal canal | A canal receiving its supplies from the headworks and in turn supplying water to the laterals, branch canals or distributaries. ..... |
| 4762 | Main control panel | Enclosure containing the main control as well as the other controls used for starting and stopping an irrigation machine...... |
| 7781 | Main drain | See 5323 and 7780...... |
| 5323 | Main drain, or Conducting drain | Principal drain that conveys drainage water from the collector drains, branch drains or submain drains to an outlet...... |
| 5058 | Main drainage system | System that conveys drainage water from the field drainage system to an outlet. It may consist of a main drain, submain drains, branch drains and coll..... |
| 4760 | Main electric cable | Cable connecting the electric point to the motor of the irrigation machine...... |
| 8375 | Main frame | Large-scale high powered computer system that can handle a number of operators simultaneously...... |
| 8017 | Main levee | Levee protecting areas of great economic value (industry, agriculture, etc.). These are required to offer protection for the required degree of safety..... |
| 4772 | Main line | Pipeline of an irrigation system under pressure going from the water source to the sub-mains or to the distribution nozzle-lines...... |
| 8210 | Main memory | Usually the fastest storage device of a computer and the one from which instructions are executed...... |
| 2736 | Main spillway | The spillway designed to pass the design flood which usually comes into operation. The main spillway can be assisted by an emergency spillway in passi..... |
| 5324 | Maintenance | The operations performed in preserving irrigation or drainage canals and drain pipes, hydraulic structures, service roads and works in good or near or..... |
| 6375 | Maintenance cards | A record of each intervention by the maintenance personnel on a single, written sheet (card)...... |
