Gayanögwad's (Phyllis Eileen Wms. Bardeau, Deer Clan) English-Onöndowa'ga:' (Seneca) dictionary is a cultural and linguistic treasure trove. Eileen, a fluent first language speaker and elder, speaks and records the Onöndowa'ga:' language as she learned it from her grandmother, several generations ago before the building of the Kinzua Dam in the 1960s. This tragic treaty violation accelerated language loss by breaking up almost two century old communities at Ohi:yonö' (Allegany Territory residents, Lit. people of the Ohi:yo׳) of the Onöndowa'ga:'. She devotes her life to the preservation of the Onöndowa'ga:' language. Phyllis created Definitive Seneca: It's In The Word is a permanent tool to study culture through language. Gayanögwad has taught the language in the community, for the Seneca Nation, and at the University level. This publication should be in every library for students of the Onöndowa'ga:' Gawë:nö׳ (Language of the People of the Great Hills).