Aftermost

All the after-most part of the ship, is called the sterne (by a generall appellation) but most exactly considered, only the very outwardmost part abaft is the sterne;

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My station during the engagement was on the middle-deck, where I was quartered with another boy, to bring powder to the aftermost gun;

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[…] at night I slept on a blanket thrown on the deck boards at the aftermost end of the round-house, and right in the draught of the two doors.

Source: wiktionary

1653, Peter English, The Survey of Policy, Leith, Section 1, Subsection 1, p. 99, In this sense Aristotle’s words hold good, if he refer the former part of the fourth species to the after-most times and ultimat center of Heroicisme, and the latter part to the prior, though not to the first times thereof.

Source: wiktionary