This is the 295th most frequent Italian word.
terzo
"Terzo" means "third" in English.
The word 'terzo' is used as an ordinal number indicating position, i.e., 'third'.
Il terzo libro della serie è il mio preferito.
The third book of the series is my favorite.
The word 'terzi' is used as a fraction, representing one part of something divided into three equal parts.
Abbiamo diviso la torta in terzi per condividerla tra noi tre.
We divided the cake into thirds to share it among the three of us.
The word 'terzo' is used here to mean an additional or alternative opinion, numerically identified as the third.