Webster's Revised Unabridged Dictionary · 1913

Mid

Mid (mid) , adjective

[Anglo-Saxon midd; akin to Old Saxon middi, Dutch mid (in comp.), Old High German mitti, Icelandic mier, Gothic midjis, Latin medius, Greek me`sos, Sanskrit madhya. r271. Compare Amid, Middle, Midst, Mean, Mediate, Meridian, Mizzen, Moiety.]

1.
Denoting the middle part; as, in mid ocean.
No more the mounting larks, while Daphne sings, Shall list'ning in mid air suspend their wings. — Pope
2.
Occupying a middle position; middle; as, the mid finger; the mid hour of night.
3.
(Phonetics) Made with a somewhat elevated position of some certain part of the tongue, in relation to the palate; midway between the high and the low; -- said of certain vowel sounds; as, ā (āle), e (ell), ō (ōld). See Guide to Pronunciation, §§ 10, 11.

Mid is much used as a prefix, or combining form, denoting the middle or middle part of a thing; as, mid-air, mid-channel, mid-age, midday, midland, etc. Also, specifically, in geometry, to denote a circle inscribed in a triangle (a midcircle), or relation to such a circle; as, mid-center, midradius.

Mid , noun

Middle. [Obsolete]
About the mid of night come to my tent. — Shakespeare

Mid , preposition

See Amid.