In most computer languages, arrays are numbered from 0 to n. Let's say we have an array of 5, it would be referenced ordinally. Let us presume we have an array called "Q"
Q[0]
Q[1]
Q[2]
Q[3]
Q[4]
As Q[0] is the first (ordinal) element in the array, it's the one you START WITH. a/k/a the leader.