cancel v.

"fact of being imprisoned," 1530s, from Medieval Latin incarcerationem (nominative incarceratio), noun of action from past-participle stem of incarcerare "to imprison," from in- "in" (from PIE root *en "in") + carcer "prison, an enclosed space," from Proto-Italic *kar-kr(o)-, which is of uncertain origin.

It seems best to connect carcer with other IE words for 'circle, round object', such as [Latin] curvus, [Greek] κιρκος 'ring', [Old Norse] hringr, although not all of these have a good IE etymology. The reduplication in Latin carcer could be iconic; thus, the original meaning would have been 'enclosure'. [de Vaan]

The word appears earlier in English in an obsolete medical sense of "retention of pus" (early 15c.).

also cancelation, "act of cancelling," 1530s, from Latin cancellationem (nominative cancellatio), noun of action from past-participle stem of cancellare "to cancel" (see cancel). Of reservations for conveyances, hotels, etc., from 1953. Earlier (early 15c.) in medical writing, in reference to the crossing of retinal images.