expression, adverb
far away in the distance; in the far distance
Describes something located or happening at a great distance, often with a poetic or emphatic feel.
遥か遠くに山々が見える。
Mountains are visible far away in the distance.
彼の声は遥か遠くから聞こえてきた。
His voice came from far away.
遠く simply means 'far away' or 'distant place'; 遥か遠く adds emphasis on the great distance, often with a more literary or dramatic nuance.
Compound of 遥か (far, distant) and 遠く (far away, adverbial form of 遠い). The exact historical derivation is straightforward; the phrase is a common emphatic expression.