1) the Red Sea
1a) the Indian Ocean washing the shores of Arabia and Persia, with its two gulfs, of which the one on the east is called the Persian Gulf, the other on the opposite side the Arabian. In the NT the phrase denotes the upper part of the Arabian Gulf (the Heropolitie Gulf, so called [i.e. the Gulf of Suez]), through which the Israelites made their passage out of Egypt to the shore of Arabia.
Part of Speech: adjective
Of uncertain affinity; red, that is, (with G2281) the red Sea: - red.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root ἐρυθρός; click on the second column to search for that grammatical form of the root ἐρυθρός; click on the third column to search for that word and grammatical form; click on the total to search for the root ἐρυθρός.