To be sure, it is the most common meaning, which is why it is listed first.
( ( To ( be sure ) ) ( , ( it ( ( is ( ( ( the ( ( most common ) meaning ) ) , ) ( which ( is ( why ( it ( is ( listed first ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (S (VP (TO To) (VP (VB be) (ADJP (JJ sure))))) (, ,) (NP (PRP it)) (VP (VBZ is) (NP (NP (DT the) (ADJP (RBS most) (JJ common)) (NN meaning)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (SBAR (WHADVP (WRB why)) (S (NP (PRP it)) (VP (VBZ is) (VP (VBN listed) (ADVP (RB first))))))))))) (. .)))
The lesser common definitions tend to be the first ones to be listed.
( ( The ( ( lesser common ) definitions ) ) ( ( tend ( to ( be ( the ( first ( ones ( to ( be listed ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (ADJP (JJR lesser) (JJ common)) (NNS definitions)) (VP (VBP tend) (S (VP (TO to) (VP (VB be) (NP (DT the) (JJ first) (NNS ones) (S (VP (TO to) (VP (VB be) (VP (VBN listed)))))))))) (. .)))