The spelling of the word "eubstance" is incorrect as there is no such word in the English language. However, the correct spelling is "substance," which is pronounced /ˈsʌbstəns/ (suhb-stuhns). The first syllable is pronounced with the short vowel sound "uh" /ʌ/ and the stress is on the second syllable. "Substance" refers to the material that things are made of, and it is a commonly used word in science, medicine, and everyday language.