When talking about a position or location, "close to the side" could be referred to as being near the edge or adjacent to the border. Additionally, it could be described as being in proximity to the margin or on the periphery. If referring to something that is tight against the side, it could be described as being flush or snug against the edge. Another term that could be used is abutting, which means to be in direct contact with. Depending on the context, "close to the side" could have various synonyms that accurately convey the intended meaning.