Cuem refers to the visible product of cueing. In other words, cuem solely refers to what can seen. The term is a portmanteau taken from words cue and mouth. It was first used by Fleetwood and Metzger in their book, Cued Language Structure.
The term cuem was likely coined because other terms (i.e., Cued Speech, cueing) are frequently defined not only in terms of features but with recommendations for use. For example, a speech-language therapist may suggest that one should always speak while cueing. While this may afford certain benefits for some, it is an application and not a requisite feature of cueing or Cued Speech. In order to answer the question, "Does cueing clearly and sufficiently convey English through a visual channel?", Fleetwood and Metzger needed to clearly delineate the visual products of cueing without confusion of added effects of simultaneously delivered speech.