Dictionary definitions give us descriptive atheism; however, descriptive atheism isn’t the entire story.  Descriptive atheism is disbelief in gods.  Prescriptive atheism is also disbelief in gods, but it is also disbelief in beings associated with gods (i.e. souls, spirits, demigods, angels, demons, etc.), disbelief in the supposed authority of religious scriptures, disbelief in religious doctrines (i.e. there is only one god (Allah) and Muhammad is his messenger; salvation through Jesus Christ), and disbelief in afterlife conceptions (i.e. heaven, hell, narakas, jahanam, reincarnation).  In short, atheism isn’t just disbelief in gods, but it is the disbelief of all that is associated with the gods.  Of course, one’s level of certainty can vary, but I think the prescriptive definition is more fitting.  Have you heard of an atheist who disbelieves in Yahweh but believes there’s a hell?  Of course not.  Are there atheists who disbelieve in gods but believe in reincarnation?  Buddhists.  According to the descriptive definition, they are atheists; however, they aren’t atheists according to the prescriptive definition.

Note:  This isn’t another “sub-category” of atheism (i.e. atheism +).  Prescriptive atheism is simply a better definition of who we actually are.  We not only disbelieve in gods, but we generally disbelieve in all that is associated with the gods.  Therefore, a prescriptive definition better suits atheism.