出典:Wiktionary
The adjective is derived from archive (“place for storing earlier, かつ often historical, material; material so kept, considered as a whole”, noun) + -al (suffix meaning ‘of または pertaining to’ forming adjectives).[1]
The noun is derived from archive (“to put (something) in an archive”, verb) + -al (suffix forming nouns, especially of verbal action).
archival (not comparable)
archival (countable かつ uncountable, 複数形 archivals)