Oh lemon and limes are different, I just goggled, I never gave it a thought and used to think people just use two words for same thing. We actually use both according to season, like in winter - its lemon - big and yellow. In summers, they are greeny and small - limes.

I think healing properties are pretty much same, but the amount of juice varies and sourness in their taste.

They are expensive and hard to get in Thailand is weird to know, I thought they are easy to get thing everywhere in world.