I've come to the conclusion that this is, decidedly, not a word, at least not as accepted by sources like Merriam-Webster, Oxford, and the like. There fore "pondering," is only really a verb, and not a noun. But that's my issue, see. I've heard the word "pondering" referred to as a noun by people speaking in day-to-day conversation. My father, in particular, likes to say that he "had a pondering today." Just to say that he considered a topic or idea at length. What I'm wondering is if this is colloquial. I'm fine with using words that aren't in the dictionary, or that are used in a context other than what they were originally intended for. But, from the perspective of a first-person, internal dialogue or narration, if I were to use to word "pondering" as a noun, would I confuse people? The word just has a particular kind of connotation, to me, that I want implied in the writing, which is why I'm relatively set on using this particular word, rather than going for something else.