When it comes to synonyms for the phrase "window oyster," there are a few different options to choose from depending on the context in which the phrase is being used. One potential alternative is "window clam," which offers a similar visual image to the original phrase. Another possibility is "window mollusk," which offers a more general term that could be applied to a variety of different shellfish. A third option is "window shell," which focuses on the hard outer casing rather than the soft inner body of the oyster. Ultimately, the best synonym will depend on the specific use case and the desired connotations and imagery.