The word Edom means “red” in Biblical Hebrew.
Red coat or Redcoat is a historical term used to refer to soldiers of the British Army because of the red uniforms formerly worn by the majority of regiments. From the late 17th century to the early 20th century, the uniform of most British soldiers.
The Papal shoes are the red leather outdoor shoes worn by the Pope. They should not be confused with the indoor papal slippers or the Episcopal sandals, which are the liturgical footwear proper to all Latin Ritebishops.
As did many noblemen, the Pope wore slippers (pantofole) inside his residences and leather shoes outside. The indoor papal slippers were made of red velvet or silk and were heavily decorated in gold braid, with a gold cross in the middle.
The papal shoes, along with the camauro, papal mozzetta, and cloak (tabarro), are the only remnants of the former red color of the papal garments. St. Pope Pius V (1566 – 1572), who was a Dominican, changed the papal color to white, and it has remained so since.
Episcopal Churches have the red doors.
‘Red is the color of the Passion. Red doors say that symbolically we enter the church the Passion, through death and resurrection in baptism (at an Orthodox baptism, the godparents present the candidate with red shoes as a symbol of walking the way of the cross)
In Greece, eggs are dyed red for good luck at Easter time.
The ancient Egyptians considered themselves a red race and painted their bodies with red dye for emphasis.
Some of this info is from here :
Red is the color most commonly found in national flags.
“Speak to the people of Israel, and bid them that they make them fringes in the borders of their garments throughout their generations, and that they put upon the fringe of the borders a thread of blue;
39. And it shall be to you for a fringe, that you may look upon it, and remember all the commandments of the Lord, and do them; and that you seek not after your own heart and your own eyes, which incline you to go astray;
40. That you may remember, and do all my commandments, and be holy to your God.”
This color Blue resembles the sea, the sea resembles the sky, and the sky resembles the “Throne of Glory,” of which it is said, “And they saw the God of Israel; and there was under his feet a kind of paved work of a sapphire stone, like the very heaven for clearness.” (Exo 24).
“And Deliverers shall come up on mount Zion to judge the mount of Esau; and the kingdom shall be the Lords.”