It's a low boiling point oxygenated hydrocarbon solvent, so it smells like you'd expect - think things like rubbing alcohol, ethanol (vodka), paint thinner (the ones that have alcohols in them).
Diethyl ether smells very "heavy", for lack of a better word, and pungent. It's almost overpowering, and can become unpleasant after a while.
Tetrahydrofuran (which is just diethyl ether with both ends of the ethyl groups bonded to form a ring) has a "lighter" smell, isn't overpowering and smells "clean" to me. It's still a oxygenated solvent, so it's not pleasant like the smell of flowers or spices, but to me it's more similar to ethanol which is relatively pleasant.
>I am left wondering if anything approaching a "standard" exists for smells ...
You can buy tasting kits for whiskey or wine. They include individual scents like peaty, smokey, oaky, blackberry even some weird ones like band-aid. You can use them to train your nose to deconstruct the smell of whiskey or wine.
It's really eye opening (or nose opening if you will). Since you might even find you suddenly agree with the tasting notes on the bottle.
Interesting. Also, if I may, it seems to me there's more individual variation in "smell discernment" ability among individuals than there is for other senses.-
ie. so called "super-noses" vs. "scent deaf" people.-
As a side note, ether is a lovely smell diluted but inhaled concentrated (for recreational purposes – it's a bit like alcohol in effect) it's bloody brutal, burning your nose & lungs.
(They used to be sweets in the UK called Victory V's which contained a very small amount of ether, and they were just lush. Bought some recently and found whatever additives that was had been removed, oh woe :) )
May I ask what it smells like?