sextodecimo
Concise Oxford English Dictionary © 2008 Oxford University Press:
sextodecimo /ˌsɛkstə(ʊ)ˈdɛsɪməʊ/ (abbrev.: 16mo)
▶noun (pl. sextodecimos) a size of book page that results from folding each printed sheet into sixteen leaves (thirty-two pages).
– origin C17: from L. sexto decimo, ablative of sextus decimus ‘sixteenth’.
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