In vector requirements for the title and keywords is written: “Do not use… types of content (examples: vector or illustration) as keywords or in your title”. (https://helpx.adobe.com/stock/contributor/help/vector-requirements.html). And there is an example, in which there is “illustration” (in the title and in the keywords — Illustration of Boxer dog with glasses) (https://helpx.adobe.com/stock/contributor/help/titles-and-keyword.html?cq_ck=1503004179722). Can I use “illustration” in the title and keywords? I have vector illustration. I wouldn't call it either poster or background. Because it is a real illustration
Please do not use illustration as a keyword. Adobe Stock already has filters for assets that are illustrations it's not necessary to use it as a keyword.