Some of the abbreviations we use in the RC world:
RTR – Ready to run – You buy the model, charge the batteries and it is ready to run.
ARTR – The model is almost ready, but you need to buy a radio and receiver and in some cases also some servos. (Many people already have radios, and don’t need another one as they can use the same radio for more than one model.)
PNP – Plug and Play – The same as ARTR
Kit – The model is supplied in pieces and needs to be constructed or built.
BNF – Commonly used in model aircraft but it means the model has a built-in receiver which needs to be binded (paired) with the transmitter.