I always call it “tin foil.” I know that it isn’t made out of tin, of course, but it always gets a cute eye-roll and smirk from Mrs. fidelis.
I was born in 1967 and I still say “tin foil.” Probably imitating my parents because there was “tin foil” before the aluminum kind that we all take for granted. I haven’t researched the history but I’m guessing that’s why.
Foil used to be made out of tin, but was replaced with aluminum.
Same reason there are no “tin cans” anymore.