Sentence:  Outstanding among these is the idea of human nature itself , including the <WSD>many</WSD> definitions that have been advanced over the centuries ; also secondary notions such as the perfectibility of man , the depravity of man , and the dignity of man . 
Meaning of the word marked with <WSD> tags:  a quantifier that can be used with count nouns and is often preceded by `as' or `too' or `so' or `that'; amounting to a large but indefinite number