We didn't really have modern, multi-section symphonies until the 1700s. Before then, the word covered many different concepts, going all the way back to Ancient Greek, so we'll be seeing quite a bit of shift here. When we first borrowed the word from Old French simphonie in the early fourteenth century, it meant "stringed instrument" in general. Before then, as Latin symphonia, it meant "harmony" (the connection, of course, being that stringed instruments can sound quite harmonious), with the same meaning and spelling in Greek. Now as we go further back in time, we can break up the word into two parts: syn-, meaning "together", and phone, meaning "sound" (and the same root as in the word telephone). Syn- comes from Proto-Indo-European sem, meaning "with", and phone comes from the PIE reconstruction bha, or "to speak". So a symphony is" speaking with" or "sounds together".
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd