It’s only recently that I’ve started to believe that “cour” is in fact a word and not just a misspelling of “cur” (as in “that cur of a cour”). As it’s entered into the lexicon of anime over the past couple of years (AnimeNano puts its first use in English around 2011) it has become an easy shorthand for how long an anime series will run for. That word “series” ends up being problematic because - for me at least - it can now mean a whole multitude of things, thanks primarily to the introduction of “split cours”.
As Wikipedia informs me, referring to a television broadcast (internet streaming simulcast etc.) as a “series” is a chiefly British use of the term, and in North America the more common term is “season”. “Season” works better when referring to something like anime because apart from a select few (One Piece et. al.), they can be measured in seasons i.e. winter, summer etc. and substituting “season” for “cour” isn’t exactly complex. However, semantically a problem arises when, as is becoming increasingly common, an anime runs for one season, lies fallow, and then finishes in another. The split cour.