Earth is the ground that we live on. It can primarily refer to two things: the planet Earth or the dirt beneath us.
The word earth was inherited from Germanic. The original spelling was eorðe which contains an obsolete letter: eth ð. The eth was eventually replaced with the thorn þ and eventually -th. In Middle English we actually see eorthþe containing both the thorn and -th. As spelling became more standardized in the Middle English era, there was a lot of trial and error to find the "correct" spelling. Middle English brought us erh, herdethe, and vrthe. Around the 1600s is when the majority of spellings had been narrowed down into earth. This vast change in spelling appears to be a combination of palatalization, consonant deletion, and the strike of the printing press. The printing press did not contain the eth or the thorn, leaving writers to choose other letters to take their place along with a reduced character count.
Due to the constancy of the earth, it is one of the main elements that we refer to in witchcraft and paganism. Earth is referred to in most rituals due to its importance in creation and life. It is also very important in Christianity as Adam was made from the earth at the beginning of creation.
Sources:
“Earth, N. (1).” Oxford English Dictionary, Oxford UP, June 2024, https://doi.org/10.1093/OED/5000214824.
The Bible. Hebrew Pub. Co.