It’s organized similarly to a tree diagram. If it has x characteristics go to this section, if it does not then go to this section. Repeat a few times and you find out what your thing is. What are those called?
a dichotomous key
This is the accurate answer. The term you may be looking for is “field guide” – a reference work intended for use out in the field that includes a dichotomous key, to allow one to identify species by sequentially answering big or small, black or white underbody, red markings or not type questions.
Right! I was trying to dig it out of my brain all day. Thanks 