(en-superlative of); the very deepest within; farthest from the surface or external part.
(ux)
{{quote-journal|en|date=2013-06-14|author=Jonathan Freedland
That which is innermost; the core.
{{quote-text|en|year=1977|author=Michael Spence Lowdell Morris|title=The Spirit of Michael Webfoot|page=10