uppermost (adj.)

c. 1300, originally comparative of up (adj.). Similar formation in Middle Dutch upper, Dutch opper, Low German upper, Norwegian yppare.

Upper hand "advantage" is late 15c., perhaps from wrestling (get the over-hand in the same sense is from early 14c.); lower hand "condition of having lost or failed to win superiority" (1690s) is rare. Upperclassman is recorded from 1871. Upper crust is attested from mid-15c. in reference to the top crust of a loaf of bread, 1836 in reference to society. Upper middle class (adj.) is recorded from 1835. Upper ten thousand (1844) was common mid-19c. for "wealthier and more aristocratic part of a large community;" hence uppertendom.

superlative suffix of adjectives and adverbs, Middle English alteration (by influence of unrelated most) of Old English -mest, a double superlative, from -mo, -ma (cognate with Latin -mus; compare Old English forma "first," meduma "midmost") + superlative ending -est. Now generally mistaken as a suffixal form of most.