The word 赤壁 is formed by combining the character 赤, meaning "red", with 壁, meaning "cliff" or "wall", to directly denote a red-colored cliff, which is the literal description of the geographical feature that gives the location its name.
Word Definition - 赤壁
chì bìRed Cliffs, historic battlefield in Huangzhou District 黃州區|黄州区[huángzhōu qū], Huanggang 黃岡市|黄冈市[huánggāng shì], Hubei, site of the Battle of Red Cliffs in 208 AD