hundredth (adj., n.)

"next in order after the ninety-ninth; an ordinal numeral; being one of one hundred equal parts into which a whole is regarded as divided;" early 14c., "one of 100 equal parts," from hundred + -th (1). According to OED, Old English had no ordinal form. The hymn tune known as Old Hundredth is attested from mid-16c., so called because later it was set to the 100th Psalm in the old numbering of the psalter.

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Definitions of hundredth from WordNet
hundredth (n.)
position 100 in a countable series of things;
hundredth (n.)
one part in a hundred equal parts;
Synonyms: one-hundredth / one percent
hundredth (adj.)
the ordinal number of one hundred in counting order;
Synonyms: centesimal / th