[adverb] [not gradable] [specialized]The disk is housed in a hermetically sealed unit to protect it from dust.(figurative) We drove past a row of squalid shacks to our hotel, where we slept in air-conditioned, hermetically sealed rooms (= rooms free from the dust, dirt and noise of the surrounding area).
HERMETICALLY
Meaning of HERMETICALLY in English
Cambridge English vocab. Кембриджский английский словарь. 2012