On logbook entries, there were of course the printed columns with date and hours etc but what one put in detail was up to the individual. Given the space, most people used just the one line with personal cryptic abbreviations. They could be read and understood by someone on the same sqn and someone familiar with the type could probably make a stab at an accurate decode.
In my case I have some that list an Exercise and a mission number, written in the assumption that the primary exercise documents would have the necessary amplifying detail.
My uncle went missing on sortie lacconically described as Searchlight Coop. Whether that meant he was acting as a practice target or was intended as the shooter if the searchlights comes a target I don't know.