The two things I associate the word lozenge with are those tablets for sore throats and Piet Mondrian's paintings on rotated canvases. Apparently, it can also mean "charge in the shape of a diamond" in heraldry, and all of those senses come from an earlier meaning of "rhombus". The heraldry and painting things are rhombus-shaped, and the original cough drops were also shaped like diamonds. The noun comes from Old French losenge, and that has an unknown origin. However, it's related to words like Spanish losange, Catalan llosange, and Italian losanga, so some etymologists think that it could be from a pre-Indo-European Celtic word, possibly meaning something like "slab". According to Google Ngrams, usage of lozenge peaked in 1872 and has been declining since.
Hello! I'm Adam Aleksic. This year, I graduated from Harvard University with a degree in Government and Linguistics. There, I co-founded the Harvard Undergraduate Linguistics Society and wrote a thesis on Serbo-Croatian language policy, magna cum laude. In addition to etymology, I also really enjoy philosophy, trivia, vexillology, geography, board games, conlanging, art history, and law.