[iamevn]

> Because Shirobako was popular.

It's been widely used long before Shirobako. But otherwise yeah. It's the subdivision of a season of a show (group of episodes produced together) that fits within a season of television (around 12 weeks). The options in English are too clunky or not specific enough for the context in which people say "cours".

I always get a kick of hearing people hesitate when deciding whether to pronounce it French-like, English-like, or Japanese-like.

[glandium]

The Japanese word comes from French, FWIW. It's also not specific to Anime. It's a term commonly used in the Japanese TV industry. It's kind of fascinating that "cours" is the more seasonal term (as it refers to a period of time matching seasons), and that none of the original terms (クール and 期) are literally related to seasons (as opposed to English where season is used for periods that nowadays have nothing to do with seasons).