meso-comb. form

Etymology: < ancient Greek μεσο-, combining form of μέσος middle (see mid adj.). Earliest in loans ultimately from Greek, as mesaraeum n., mesenterium n., mesograph n., mesolabe n., mesozeugma n. English formations (which are chiefly scientific, although compare the early mesology n. and mesothesis n.) are attested from the early 19th cent. (discounting the isolated early formation mesonoxian adj.). Compare J. Barclay's slightly earlier formation mesial adj. and compounds after this in mesio- comb. form. French formations in méso- and German formations in meso- are also attested from the early 19th cent. Many scientific formations in meso- comb. form have correlates with meta- prefix and with pro- prefix¹ or proto- comb. form. Formations in sense 1b are after mesentery n. and mesocolon n., and are attested from the early 19th cent. Formations in sense 1c are after mesencephalon n.; earliest in mesolimbic adj. N.E.D. (1906) gives only the pronunciation (me·so) /ˈmesoʊ/. Variants in which the first syllable is pronounced with a long vowel appear to represent spelling pronunciations, rather than the outcome of any regular phonetic development. They are first explicitly recorded in dictionaries of the first half of the twentieth century, although the absence of earlier evidence may perhaps reflect conservatism motivated by an awareness of the short vowel in the classical Greek etymon. Similarly, sporadic instances of spellings in mezo- (see, for example, mesotype n. and mesozeugma n.) show clearly that the tendency for the sibilant to become voiced intervocalically has operated throughout the history of the form, despite the failure of reference works from before the twentieth century to record this fact. The position of the stress differs between compounds of meso- in accordance with the general stress patterns of English. Contrastive stress may also give rise contextually to primary stress on the first syllable of the prefix in compounds where the stress ordinarily falls elsewhere.