I like intention revealing names, that is, phrases or names of things that describe what they are referring to. There are currently two phrases for WIP. The more popular one is “work in progress” whereas the more accurate is “work in process.” This difference is not academic as the usage of 'progress' can lead to bad practices.
Progress means “forward or onward movement toward a destination.” But WIP refers to work that has started but hasn’t been completed. Work may be blocked, that is, not progressing at all. Work in progress (in English) does not include blocked work. But it is WIP. This has led many teams new to kanban to not include items that are blocked (not progressing) towards their WIP limits. This is not effective.
“In process” means “of, relating to, or being goods in manufacture as distinguished from raw materials or from finished products.” English tells us that something blocked is not in progress but is in process.
It’s worth having our words mean what is inferred by their common definitions.
It is interesting to note that Scrumban (the first book on Kanban) used process, as does Don Reinertsen’s work.