From Longman Dictionary of Contemporary Englishheavy schedule/timetable/day etcheavy schedule/timetable/day etcLOT/LARGE NUMBER OR AMOUNTa time in which you have a lot to do Let’s go to bed. We’ve got a heavy day tomorrow. → heavy
Examples from the Corpus
heavy schedule/timetable/day etc• The distant baying of a hound tugged at the heavy day.• Quite apart from the vines, I have a heavy day ahead of me - a lot of serious talking to do.• I understand the importance of the statement, but we have a heavy day ahead of us.• We have a very heavy day ahead of us.• But Joe was concerned about the heavy schedule he had to keep in order to maintain that income. 