What are the objects call that transform data between layers

I have a question about what is the convention for naming objects the transform one object into another. I swear there was an elegant name for this that I'm forgetting and all my searches just end up with the difference between a DTO and and Entity or Model or DAO or POCO or POJO.

I'm not interested in using Automapper at this point either, I might convert to that later, but the code is there, I just want to name it correctly!