[ rah ]
/ rɑ /


the 10th letter of the Arabic alphabet.

Words nearby

Origin of

From Arabic

Definition for ra (2 of 5)

[ rah ]
/ rɑ /

noun Egyptian Religion.

a sun god of Heliopolis, a universal creator worshiped throughout Egypt (typically represented as a hawk-headed man bearing on his head the solar disk and the uraeus).
Also Re.

Definition for ra (3 of 5)


Symbol, Chemistry.

Definition for ra (4 of 5)


regular army.

Definition for ra (5 of 5)


rear admiral.
Astronomy. right ascension.
royal academician.
Royal Academy.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for ra

British Dictionary definitions for ra (1 of 3)


the chemical symbol for


British Dictionary definitions for ra (2 of 3)



/ (rɑː) /


the ancient Egyptian sun god, depicted as a man with a hawk's head surmounted by a solar disc and serpent

British Dictionary definitions for ra (3 of 3)


abbreviation for

rear admiral
astronomy right ascension
(in Britain) Royal Academician or Academy
(in Britain) Royal Artillery
Argentina (international car registration)

Word Origin for RA

(sense 5) from República Argentina
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for ra


The symbol for the elementradium
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for ra (1 of 2)


The symbol for radium.

Scientific definitions for ra (2 of 2)

[ rādē-əm ]


A rare, bright-white, highly radioactive element of the alkaline-earth group. It occurs naturally in very small amounts in ores and minerals containing uranium, and it is naturally luminescent. Radium is used as a source of radon gas for the treatment of disease and as a neutron source for scientific research. Its most stable isotope is Ra 226 with a half-life of 1,622 years. Atomic number 88; melting point 700°C; boiling point 1,737°C; valence 2. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.