'mask-friendly' originates from Modern English as a compound of 'mask' and 'friendly'. 'Mask' refers to a face covering and 'friendly' means 'suitable for' or 'beneficial to'.

'mask' traces back through Middle French/Italian: Italian 'maschera' (mask) and Middle French 'masque' entered English as 'mask'. 'Friendly' comes from Old English 'frīendlic' (from 'frīend' meaning 'friend' + '-lic'), developing into Modern English 'friendly'. These elements combined in recent English usage to form the descriptive compound 'mask-friendly'.

Initially, the components meant 'a face covering' and 'having the qualities of a friend/being suitable'. Over time they combined to form a modern compound meaning 'suitable for use with a mask' (i.e., designed not to interfere with mask use).