[ep-uh
k-mey-king or, especially Brit., ee-pok-] 
| opening a new era, as in human history, thought, or knowledge; epochal: an epoch-making discovery. |
| ep·och-mak·ing (ěp'ək-mā'kĭng, ē'pŏk-) adj. So significant and momentous as to characterize the beginning of a period: the President's epoch-making trip to China; epoch-making new technologies. |