This is the 12690th most frequent Portuguese word.
trigésima
"Trigésima" means "thirtieth" in English.
In this sentence, "trigésima" is used as an ordinal adjective modifying the noun "página," meaning the thirtieth instance in a sequence of pages.
A trigésima página do livro é crucial para entender a trama.
The thirtieth page of the book is crucial to understand the plot.
Here, "trigésimo" is used as an ordinal adjective modifying "aniversário," reflecting the count of birthdays reaching thirty.
Ela comemorou seu trigésimo aniversário com uma grande festa.
She celebrated her thirtieth birthday with a big party.
In this case, "trigésimo" is used to quantify a specific day in a sequence, the thirtieth consecutive day.