The United States Patent and Trademark Office (USPTO) uses a field code called Pseudo Mark. The Pseudo Mark field code is used to help users identify relevant trademarks related to their search. Pseudo Marks contain spellings that are similar or phonetically equivalent to the word trademark. For example, if 4U appears in the trademark, the term for you would be added to the pseudo-mark field. This provides an additional search tool for locating trademarks that contain an alternative or intentionally corrupted spelling for a normal English word.
Users can search trademarks using the Pseudo Mark field code by using either the structured search or free form search on the USPTOs website.