average
betwixt and between
central
core
equatorial
equidistant
half-and-half
halfway
in medias res
in the mean
in the middle
interior
intermediary
intermediate
mean
medial
medially
median
mediocre
mediterranean
medium
mediumly
mesial
mezzo
mezzo-mezzo
mid
middle
middlemost
middling
midland
midmost
midships
midway
nuclear