I suppose there is some standard taste chart set ( some wheel I've seen on various forums ) to express the taste by "assigned" key words. Yet , I do not posses knowledge of those and I believe I'm not the only one. So when it comes to the taste and smell description ( and they are connected ) , I use my personal experience ( from life ) to do so.
Examples:
wet leaves in the forest after the rain - once we had some pressed huang pian which were partially Guangzhou storage. HP have usually those sweet notes , sometimes fruity , honey but also can have sort of medicinal notes ( which could be mix of sweet & sour taste ) , it may also have the cardboard ( which could be mix of bitter & sour ? ) which mostly appears in shu version. Sometimes also can have slight earthy notes and that was the combo we had in our HP back then. When pouring hot water on that , the aroma reminded me the times we use to go as children with father to the forest pickup some mushrooms and I was raking the wet leaves in order to find some mushrooms hiding under. Same resembles when I ride my MTB in forest after rain and tires slicing trough the mud covered by those fallen wet leaves. ...and I could go on

I'm sure there is some 1 or 2 keywords adequate to this aroma / taste , but I just don't know them and I do not expect regular tea drinker to know that either , so I don't feel to learn and use those at the first place. But I do believe, that many of us have walked trough the forest after rain though.
The scent of fresh melting snow in early spring - that's what I remember from childhood when eating snow. Similar notes resembled later when coming back from mountains on snowboard trough the narrow path and the bottom of the hill snow was already melting so had to walk in slushy melted snow . That snow aroma blended with pine trees aroma is exactly what I smell in Ya Bao

I understand when people say " oh this vendor just exaggerating with notes " and I agree that some do. Not only vendors. Just look at the steepster. Specially beginners who want to "fit in club of cool guys" trying to add any possible tasting tag to the tea they reviewing.
And yes, no vendor will tell about his tea is just mediocre , I did few times on budget drinker and it was just like I didn't have to bother to put it on shop at the first place ;-D ...nobody buy it.
When you have one tea in 2 different qualities and so the prices , the worst thing you can do is , that the lower quality you describe as lower quality ( describe its downsides compare to the first one ) . I'm sure I still have that kind of description on some products ( like when have Gushu and Xia Shu of the same garden, or spring versus autmn for example ) .
Buyer naturally want's the best for him / her self so anything with "negative" sound is omitted from attention at very beginning. So I do not blame vendors ( and I probably use some of that technique my self ) when characteristic like dry sensation is replaced with persimmon or banana skin to sound more gentle and attractive ( for some people of course ).
I think I even criticize it on my blog somewhere , but in time I came to the conclusion that this might be a necessary marketing vocabulary for driving the sales.
At the end of the day , you ..as a internet tea buyer , can rely only on pictures and description before decide spend your $ for sample. Trusted vendor option is other topic.
Anyway, please feel free to throw some other descriptions below . Good / bad ones, ridiculous or very funny ones.
Once customer ( US ) sent me a sample of shu . I tasted cardboard but he tasted baked cornflakes ...I don't know , never tried that thing.