Earlier quoted context omitted.
In Polish months are named after plants that bloom then and weather conditions. Quite poetic to say "I will meet you on the 5th day in the month of linden trees" :) The funny thing is that other Slavic countries use similar names but some are moved 1 month back or forth because flowers bloom earlier/later there :) And days of the week are simply numered starting with sunday = "niedziela" (not working day), "poniedzia…
Interesting. So my grandmother's maiden name "wrzesień" has a meaning beyond "September" (according to Polish-English translations)? I don't know for a fact it had the accent over the last letter. Records here in the US exclude it, of course that hardly means it wasn't there originally.
Also it's not accent, it's softening of the n sound, similar to Spanish n with ~.