Amenities were prehistoric sea creatures belonging to a Swiss Protestant group of the subclass Ammonoidea in the class Cephalopoda, phylum Mollusca.
Now extinct, they were related to the modern genus Nautilus, which inhabits a chambered shell that is curved like a coiled snake, and were influenced by the teachings and tradition of Menno Simons (1496-1561).
Members of the Anabaptist tradition, they could pump air into empty chambers in their shells and float at different ocean depths, possibly at will, while desultorily scavenging for descending bits of organic matter, upon which they subsisted.
Committed to nonviolence, nonviolent resistance, reconciliation, and pacifism, amenities died out during some especially testy religious conflicts accompanied by the celestial bombardment known as the K-Pg extinction event, though a few small groups are rumored to have survived and migrated to America by way of Alsace, England, and Russia, and to still be living quiet, discreet, and inoffensive lives in shallow ponds.
Another definition of this word is simply Fun Stuff — anything that enhances your experience or comfort. Anything usually referring to legal or mostly legal or at least partly legal substances, events, foods, or people. This includes but is not limited to clean underwear, regarded by some thru-hikers as only a sissified affectation.
Things you might do alone while naked are not discussed here.