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You want to give us the context from the Nabokov?


Well, it's defininitely not a hapax legomenon... I just came across it in a short story, also by Nabokov.

Here's your context:

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Just before falling sleep, I often became aware of a one-sided conversation going on in an adjacent section of my mind, quite independent from the actual trend of my thoughts. It is a neutral, detached, anonymous voice, which I catch saying words of no importance to me whatever—an English or a Russian sentence, not even addressed to me, and so trivial that I hardly dare give samples, lest the flatness I wish to convey be marred by a molehill of sense. This silly phenomenon seems to be the auditory counterpart of certain praedormitary visions, which I also know well.

—Speak, Memory: An Autobiography Revisited, p.28.


Quote:
Presently he sleeps, he sleeps, and, since, on his convict's cot, not a single praedormitory thought troubles him ...

—Tyrants Destroyed, ch. 14.