Manufacturing engineering

Map design

Map projections

Map reproduction

Maple

Marattiales

Marble

Marchantiales

Marchantiidae

Marcus equation

Margarine

Marijuana

Marine biological sampling

Marine conservation

Marine containers

Marine ecology

Marine engine

Marine engineering

Marine fisheries

Marine forensics

Marine geology

Marine machinery

Marine microbiology

Marine mining

Marine mycology

Marine navigation

Marine sediment

Marine transportation and the environment

Maritime meteorology

Marjoram

Marl

Marmot

Mars

Mars Express

Mars Science Laboratory

Marsileales

Marsupialia

Marten

Masdar, sustainable desert city

Maser

Masking of sound

Masonry

Mass

Mass defect

Mass extinction

Mass number

Mass spectrometry

Mass spectroscope

Mass wasting

Mass–luminosity relation

Massif

Mast cell

Mastigophora

Mastitis

Matched-field processing

Material resource planning

Materials handling

Materials science and engineering

Maternal behavior

Maternal influence

Mathematical biology

Mathematical ecology

Mathematical geography

Mathematical physics

Mathematical software

Mathematics

Matrix calculus

Matrix isolation

Matrix mechanics

Matrix theory

Matter

Matthiessen's rule

Maxillopoda

Maxwell's demon

Maxwell's equations

Maya civilization

McLeod gage

Mean effective pressure

Mean free path

Measles

Measles outbreak of 2011

Measure

Measure theory

Measured daywork

Measurement of aircraft fuel efficiency

Measurement of source-receiver motion with underwater sound

Measuring formaldehyde emissions from wood-based panels

Meat food safety

Mechanical advantage

Mechanical alloying

Mechanical classification

Mechanical engineering

Mechanical impedance

Mechanical properties of metal

Mechanical separation techniques

Mechanical vibration

Mechanics

Mechanism

Mechanoreceptors

Mecoptera