SID/STAR phraseology allows ATC and aircrew to communicate and understand detailed clearance information that would otherwise require long and potentially complex transmissions. Over time, these benefits have been eroded through the development of non-harmonised practices and different meanings being attached to certain elements of SID/STAR phraseology. Consequently, there may be a mismatch between ATC and aircrew expectations when SID/STAR phraseology is used, and what certain terms may mean. This presents a safety risk that requires a renewed effort to adopt harmonised SID/STAR phraseology.