petitio principii

[pi-tish-ee-oh prin-sip-ee-ahy; Latin pe-tee-ti-oh pring-kip-i-ee] /pɪˈtɪʃ iˌoʊ prɪnˈsɪp iˌaɪ; Latin pɛˈti tɪˌoʊ prɪŋˈkɪp ɪˌi/
noun, Logic.
1.
a fallacy in reasoning resulting from the assumption of that which in the beginning was set forth to be proved; begging the question.
Origin
1525-35; < Medieval Latin petītiō prīncipiī, translation of Greek tò en archêi aiteîsthai the assumption at the outset
British Dictionary definitions for petitio principii

petitio principii

/pɪˈtɪʃɪˌəʊ prɪnˈkɪpɪˌaɪ/
noun
1.
(logic) a form of fallacious reasoning in which the conclusion has been assumed in the premises; begging the question Sometimes shortened to petitio
Word Origin
C16: Latin, translation of Greek to en arkhei aiteisthai an assumption at the beginning