In Echinodermata, that area of the body surface lying between ambulacra. See ambulacrum.
Interambulacrum
- marsh gas
- Marsh’s test
- Marsilius of Padua (1275/80–1342)
- MARSIS
- Mars Observer
- Mars Odyssey
- Mars Orbiter Mission
- Mars Pathfinder
- Mars Polar Lander
- Mars probes
- marsquake
- Mars Reconnaissance Orbiter
- Mars Science Laboratory
- Mars Surveyor
- Marston Moor, Battle of (2 July 1644)
- Marsupialia
- marsupials
- marten
- martensite
- martian
- martian canals
- martian terrain units
- martin
- Martin, Archer John Porter
- Martin, Charles Burton (1924–2008)