A trance is a state of being in which consciousness is wholly or partially suspended. The same Greek word is also used in the Greek Translation of the Old Testament in reference to the sleep of Adam (Genesis 2:21) and Abraham (Genesis 15:12). It is possible that Peter fell asleep/dozed off and had a particularly vivid vision while he was sleeping/dozing.1 The fact that he is hungry before he falls into a trance is part of the reason why he is perplexed afterwards (see Acts 10:17); he is not sure if he really had a vision or if he dreamed of food as a result of his hunger.2 Peter’s hunger establishes a point of contact between his situation and the vision he receives.3
10 And he became hungry and wanted something to eat, but while they were preparing it, he fell into a trance