definition of a highlevel language?
gills: Most abstractions are a little leaky, and we usually need to consider the 'how' when specifying the 'what'.  For example, adding numbers in C can be accomplished with the abstraction '+', but the programmer must consider whether the operation will overflow the register on the underlying machine.  Some even-higher-level languages plug that leak by providing a numerical hierarchy that will not overflow due to constraints imposed by the underlying hardware.So I would say "higher-level languages" provide less-leaky abstractions.  One can specify 'what' without specifying 'how', and one can make assumptions about the way exceptional cases are handled.  The ideal language would provide leak-free abstractions but still allow the programmer to dive into any level.There is probably a lot more to say than that.