'customarily-applied' originates from the combination of 'customarily' and 'applied', where 'customarily' is derived from 'custom', meaning 'a traditional and widely accepted way of behaving or doing something'.

'customarily' evolved from the Old French word 'costume', and 'applied' comes from the Latin word 'applicare', meaning 'to attach or join'.

Initially, 'customarily' meant 'according to custom', and 'applied' meant 'put to use'. Together, they evolved to mean 'used in a customary manner'.