Program-erase cycle of MKRWAN 1310 QSPI Flash RAM

Hello, I was looking into the QSPI Flash RAM of MKRWAN 1310 (Winbond 25Q16JVIQ) and found this PDF: https://www.winbond.com/resource-files/w25q16jv%20spi%20revd%2008122016.pdf

I found a section in this document stating that it has a 100k Program-Erase cycles per sector endurance. May I know what does “per sector” mean? Thank you.