Being in the middle, or nearest the middle; midmost.
Webster 1828 Edition
Middlemost
MID'DLEMOST
,
Adj.
Being in the middle, or nearest the middle of a number of things that are near the middle. If a thing is in the middle, it cannot be more so, and in this sense the word is improper. But when two or more things are near the middle, one may be nearer than another.