Sentence:  One growth center in a short bone - distal phalanx of the second finger - was chosen as an example for discussion here , primarily because epiphyseal diaphyseal fusion , the maturity <WSD>indicator</WSD> for Completion in long and short bones , occurs in this center for girls near the menarche and for boys near their comparable pubescent stage . 
Meaning of the word marked with <WSD> tags:  a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time