Noun ra has 3 senses
- radium, Ra, atomic number 88 - an intensely radioactive metallic element that occurs in minute amounts in uranium ores
--1 is a kind of neural network, neural net; metallic element, metal; neural network, neural net; metallic element, metal
--1 is a part of reticular formation, RF
--1 is a substance of uranium ore
- right ascension, RA, celestial longitude - (astronomy) the angular distance eastward along the celestial equator from the vernal equinox to the intersection of the hour circle that passes through the body; expressed in hours and minutes and second; used with declination to specify positions on the celestial sphere; "one hour of right ascension equals fifteen degrees"
--2 is a kind of angular distance; angular distance
- Ra, Re - ancient hawk-headed Egyptian sun god; a universal creator
--3 is a kind of Egyptian deity; Egyptian deity
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