'rarely-transmitted' is a compound word formed from 'rarely' and 'transmitted'. 'Rarely' originates from Middle English 'rar', meaning 'seldom', and 'transmitted' comes from Latin 'transmittere', where 'trans-' meant 'across' and 'mittere' meant 'to send'.

'Rarely' evolved from the Middle English 'rar', and 'transmitted' from the Latin 'transmittere', eventually forming the modern English compound 'rarely-transmitted'.

Initially, 'rarely' meant 'seldom' and 'transmitted' meant 'sent across'. Together, they describe something not often sent or passed.