The word "although" is a conjunction used to introduce a contrast or an exception in a sentence. It allows us to express a condition where something happens or is true despite something else being the case. Essentially, "although" helps in making complex sentences by linking two ideas that seem contradictory.
The word "although" originated from Middle English "al, al... though," which is a combination of "all" (meaning entirely or completely) and "though" (which conveys the idea of concession). Its roots can be traced back to Old English "Ælþeah" where "æl" means "all" and "þeah" means "though."