There are a variety of synonyms for "public grade schools" that can be used interchangeably. For instance, "state schools" describes institutions that are funded by the government and aimed at providing education to children up to a certain age. "Government schools" is another synonym that is commonly used, as is "public schools," which is a more generic term that can be used for any institution that receives government funding. Additionally, "elementary schools," "primary schools," and "grammar schools" are all terms that can be used to refer to public schools that cater to students in their early years of education. Ultimately, there are many words that can be used as synonyms for public grade schools depending on the context of the conversation or written work.