'pressure-free' originates from the combination of 'pressure' and 'free', where 'pressure' meant 'the continuous physical force exerted on or against an object by something in contact with it' and 'free' meant 'not under the control or in the power of another; able to act or be done as one wishes'.

'pressure' changed from the Old French word 'pressur' and eventually became the modern English word 'pressure'. 'Free' has remained largely unchanged from its Old English form 'frēo'.

Initially, 'pressure' meant 'physical force', but over time it evolved to include psychological stress, while 'free' has consistently meant 'without constraint'.