Epizeuxis
Epizeuxis , noun
[Latin, from Greek {not transcribed} a fastening together, repetition, from {not transcribed} to fasten to or upon; 'epi` upon + {not transcribed} to join, yoke.]
(Rhetoric) A figure by which a word is repeated with vehemence or emphasis, as in the following lines: --
Alone, alone, all all alone,
Alone on a wide wide sea.