There's a Halacha/Mitzvah to say at-least 100 Brochos a day.
My question is: what does the term "day" mean in this regard. Does a day start at night, and end the following night (as is the case in most of Judaism), or is there a different time-period used for this count?
Also, assuming it starts at night, does it start at sunset or nightfall (tzeis)?