The most correct spelling is Ra.
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Neither Re nor Ra represents the word as written in hieroglyphs, so neither is "correct" in any sense. The name of the sun god is written with signs spelling two consonants: r+' (a glottal stop, also found in Arabic, Phoenician and Hebrew). Hieroglyphs did not record any vowels, so we can never know how this name was pronounced. Modern Egyptologists and students of hieroglyphs use both Ra and Re, simply to be able to pronounce R' in a communicable form.
One linguistic theory (based on contemporary foreign versions of Egyptian names containing the name of the sun god) suggests that Ria' may be accurate, but this is purely hypothesis.
To suggest that "Ra is the most correct spelling" is misleading, disingenuous and mendacious.
"Reay" is pronounced as "ray". It is a one-syllable name with a long "a" sound.
Stephen Reay died in 1861.
Reay Boathouse was created in 1928.
Lord Reay was created in 1627.
Reay Tannahill was born in 1929.
Richard Reay is 5' 11".
Stephen Reay was born in 1782.
Reay Tannahill died in 2007.
Billy Reay was born on August 21, 1918.
Billy Reay was born on August 21, 1918.
Gord Reay died on 2000-12-21.
Gord Reay was born on 1943-05-30.
Andy Reay was born on 1983-04-01.