A Word for a Period of Nighttime Wakefulness?

There’s an English word for “sleep during daytime”: nap. But is there a word for “a period of nighttime wakefulness,” aside from spelling nap backwards as pan? The French have a lovely word for this state, dorveille, a portmanteau of dormir, “sleep” and veiller, “wake.” After coming across references in journals and other historical documents to first sleep followed by a period of wakefulness, followed by second sleep, historian Roger Ekirch made a cross-cultural study of the phenomenon, which formed the basis of his fascinating book, At Day’s Close: Night in Times Past (Bookshop|Amazon). Other terms involving phases of sleep include the rare English word semisomnous, or “half-asleep,” and hypnopompic, describing “the process of waking.” In Japanese, uto-uto denotes “the process of falling into a light sleep.” This is part of a complete episode.