Meaning
A rejected name for promethium.
Etymology
Origin: Unknown
From Illinois + -ium, from the University of Illinois at Urbana-Champaign, which made an unverifiable claim to have discovered the element in 1926.
NYT Puzzle Appearances
No published puzzle dates on file for this word yet. It is part of the official NYT Spelling Bee word list for 2019, 2021, 2023, 2025, 2026.