This adverb means during the night or while it is still dark. Mark 1:35 records that Jesus rose 'very early in the morning, a great while before day' to pray in a solitary place. The term emphasizes the pre-dawn darkness, the depth of night when Jesus sought communion with the Father. Classical usage applied this to nighttime visits or activities. Mark highlights Jesus' prayer discipline: he sacrificed sleep to secure undisturbed time with God before the demands of ministry crowded in.