Other forms: entireties
The noun entirety describes something that is total or complete, like when you eat a pizza in its entirety, leaving not even one slice for other people.
The noun entirety comes from the Latin word integritas, meaning “untouched” or “whole.” If a televised football game goes long, the announcers might say, "Your local news will air in its entirely after the game." That means the news will be its normal length, not shortened. If you did your assigned reading in its entirety, it means you completed it, reading every page, not just skipping around.