'randomly-selected' originates from the combination of 'randomly' and 'selected', where 'randomly' comes from 'random', meaning 'without a definite aim, direction, rule, or method', and 'selected' is the past participle of 'select', meaning 'to choose'.

'randomly-selected' evolved from the combination of 'random' and 'select', which were used separately in Middle English and later combined in modern English.

Initially, 'randomly-selected' meant 'chosen without a specific pattern', and this meaning has largely remained the same in modern usage.