entombment
noun/ɪnˈtuːm.mənt/ · /ɛnˈtuːm.mənt/
Etymology From entomb + -ment.
1
The act of entombing or the state of being entombed
2
The decommissioning of a radioactive site by encasing it in concrete
Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.