BPM : Beats Per Minute (also know as Tempo) is something that should be familiar to most musicians. BPM is the standard way to manage time in music. It literally refers to the amount of given beats per standard minute.
What must be understood is that this is the amount of Beats Per Minute and not the amount of Rows per Minute. A row is actually equal to one tick. There for the number of rows in a minute is equal to the BPM times the TPB (i.e. Rows per minute = TPB * BPM).