The term ALMA is an acronym for the Atacama Large Millimeter/submillimeter Array, which is an astronomical interferometer of radio telescopes in northern Chile. It is composed of 66 antennas that are 12 meters in diameter and spread out over distances of up to 16 kilometers. ALMA is used to observe the universe in millimeter and submillimeter wavelengths, which are between infrared light and radio waves. The MATER part of the crossword solution refers to the ALMA Telescope Manager, who is responsible for the day-to-day operations of the telescope.