They wanted a vaguer term to describe the Father and the Son. These Semi-Arian bishops substituted the term "homoousion" in the Nicene Creed with the term "homoiousion", meaning "of like substance".

Amen. Pater noster, qui es in caelis: sanctificetur nomen tuum; adveniat regnum tuum; fiat voluntas tua, sicut in caelo, et in terra. Panem nostrum cotidianum da nobis hodie; et dimitte nobis ...