So, what is the definition of agnosticism? Some imagine that agnosticism is an alternative to atheism, but those people have typically bought into the mistaken notion of the single, narrow definition of atheism. Strictly speaking, agnosticism is about knowledge, and knowledge is a related but separate issue from belief, the domain of theism and atheism.

A means without and gnosis means knowledge. Hence, agnostic: without knowledge, but specifically without knowledge of gods.

It may be technically correct, but rare, to use the word in reference to any other knowledge as well, for example: I am agnostic about whether O.J. Simpson actually killed his ex-wife.

Despite such possible usages, it remains the case that the term agnosticism is used fairly exclusively with respect to a single issue: do any gods exist or not? Those who disclaim any such knowledge or even that any such knowledge is possible are properly labeled agnostics. Everyone who claims that such knowledge is possible or that they have such knowledge might be called gnostics (note the lowercase g).

Here gnostics is not referring to the religious system known as Gnosticism, but rather the sort of person who claims to have knowledge about the existence of gods. Because such confusion may come easily and because there is generally little call for such a label, it is unlikely that you will ever see it used; it is only presented here as a contrast to help explain agnosticism.

Confusion about agnosticism commonly arises when people assume that agnosticism actually just means that a person is undecided about whether or not a god exists, and also that atheism is limited to strong atheism the assertion that no gods do or can exist.

If those assumptions were true, then it would be accurate to conclude that agnosticism is some sort of third way between atheism and theism. However, those assumptions are not true. Commenting on this situation, Gordon Stein wrote in his essay The Meaning of Atheism and Agnosticism:

See more here:
What is Agnosticism? A Short Explanation