A hit
die is in simplest terms a 'title' given to any die used in calculating
damage in
pen and paper, and some
digital RPGs that draw their
roots from pen and paper. Its a little more
complex in that its often used to mean "the hit die are" where you have a
written structure of rolls of die, written as:
rolls d sides
so:
the hit die is as example d20
the hit die are as example 4d20
The
nature of this
structure is allowing to have a range of
randomness other than 1 to x, instead y to x, and also to effect the
probability of achieving either the lowest or highest value due to your
combination sets.
In the above example since your
rolling four 20
sided die you can't achieve less than 4, and can achieve as much as 80, and the odds of achieving 4 or 80 are 20^4th ( 1 in 160
k ) instead of with one 80 sided die 1 in 80, whereas mid
range numbers grow much more
probable with multiple die.
4d2 probability chart:
d1| d2| d3| d4| Result
1 | 1 | 1 | 1 | 4 1/16 = 4 6.25%
1 | 1 | 1 | 2 | 5 4/16 = 5 25.00%
1 | 1 | 2 | 1 | 5 6/16 = 6 37.50%
1 | 1 | 2 | 2 | 6 4/16 = 7 25.00%
1 | 2 | 1 | 1 | 5 1/16 = 8 6.25%
1 | 2 | 1 | 2 | 6
1 | 2 | 2 | 1 | 6
1 | 2 | 2 | 2 | 7
2 | 1 | 1 | 1 | 5
2 | 1 | 1 | 2 | 6
2 | 1 | 2 | 1 | 6
2 | 1 | 2 | 2 | 7
2 | 2 | 1 | 1 | 6
2 | 2 | 1 | 2 | 7
2 | 2 | 2 | 1 | 7
2 | 2 | 2 | 2 | 8