GNU poke is a new program and it introduces many new concepts. It is a good idea to clarify how we call things in the poke community. Unless everyone uses the same nomenclature to refer to pokish thingies, it is gonna get very confusing very soon!
First of all we have poke, the program. Since “poke” is a
very common English word, when the context is not clear we either use
the full denomination GNU poke, or quote the word using some
other notation.
Then we have Poke, with upper case P, which is the name of the
domain-specific programming language implemented by poke,
the program.
This distinction is important. For example, when people talk about “poke programmers” they refer to the group of people hacking GNU poke. When they talk about “Poke programmers” they refer to the people who write programs using the Poke programming language.
Finally, a pickle is a Poke source file containing definitions of types, variables, functions, etc, that conceptually apply to some definite domain. For example, elf.pk is a pickle that provides facilities to poke ELF object files. Pickles are not necessarily related to file formats: a set of functions to work with bit patterns, for example, could be implemented in a pickle named bitpatterns.pk.
We hope this helps to clarify things.