'randomly-spaced' originates from the combination of 'randomly' and 'spaced', where 'randomly' is derived from 'random', meaning 'without definite aim, direction, rule, or method', and 'spaced' from 'space', meaning 'to arrange with intervals'.

'randomly-spaced' evolved from the combination of the words 'random' and 'space', which were used separately in Middle English and later combined in modern English to describe irregular intervals.

Initially, it meant 'arranged without a specific pattern', and this meaning has largely remained the same in modern usage.