An enumerated species is one where all constructors are just members of the species, rather than being functions The definition of an enumerated species just lists the members of the species See T11
To count; to tell by numbers; to count over, or tell off one after another; to number; to reckon up; to mention one by one; to name over; to make a special and separate account of; to recount; as, to enumerate the stars in a constellation
When you enumerate a list of things, you name each one in turn. I enumerate the work that will have to be done. = itemize. to name a list of things one by one (enumeratus, past participle of enumerare, from numerare )