ra

noun

1. an intensely radioactive metallic element that occurs in minute amounts in uranium ores

   Synonyms

   • radium, Ra, atomic number 88

   Less specific

   • metallic element, metal

   Made from

   • uranium ore

2. ancient Egyptian sun god with the head of a hawk; a universal creator; he merged with the god Amen as Amen-Ra to become the king of the gods

   Synonyms

   • Ra, Re

3. (astronomy) the equatorial coordinate specifying the angle, measured eastward along the celestial equator, from the vernal equinox to the intersection of the hour circle that passes through an object in the sky; usually expressed in hours and minutes and seconds; used with declination to specify positions on the celestial sphere; “one hour of right ascension equals fifteen degrees”

   Synonyms

   • right ascension, RA, celestial longitude

   Less specific

   • angular distance