Entry 1 sense Webster, 1913 Uppermost /ŭp'-ẽrm-ōstˌ/ · Up·per·most · IPA /ˈʌpɚˌmoʊst/ 01 a. Highest in place, position, rank, power, or the like; upmost; supreme. 1. Highest in place, position, rank, power, or the like; upmost; supreme. “Whatever faction happens to be uppermost.” — Swift.