Mine is lilacs, because there was a lilac bush at the bus stop that I used to wait at with my mom when I was a kid, it was my school bus stop and the public bus stop so we spent a lot of time on that corner and now when I smell lilacs I just immediately feel like a kid again.
Rain. Or, rather, the sweet earthy smell of wet moss or grass and decomposition and the rest of it that is far beyond any human descriptions and impossible to even approach with words 🥹
Combined with the sound, it’s the most divine state a world can exist in, period.
Petrichor?
Not sure if the smell of autumn’s decomposing has a distinct word though.