The term "preliminary form" refers to an initial or early version of something. There are several synonyms that can be used to express this concept including "preliminary version", "first draft", "early stage", "preliminary outline", "rough draft", "preliminary sketch", "prototype", "dummy", "beta version" and "preliminary model". These synonyms can be used interchangeably depending on the context in which they are used. The term is often used in the context of art, design, engineering and writing. Overall, the use of synonyms for "preliminary form" can help to add variety and clarity to one's language while conveying the same essence.