This is the 10076th most frequent Portuguese word.
décimo
"Tenth."
In this sentence, 'décimo' signifies an ordinal number indicating position.
Eu sou o décimo a chegar na festa.
I am the tenth to arrive at the party.
Here, 'décima' is used as an ordinal adjective agreeing in gender with the feminine noun 'vez' to describe frequency.
É a décima vez que visito este lugar.
It is the tenth time I visit this place.
In this case, 'décimo' is a fraction describing a part of a whole.