[siks-teen-moh] 
noun, plural -mos, adjective | 1. | Also called sextodecimo. a book size (about 4×6 in.; 10×15 cm) determined by printing on sheets folded to form 16 leaves or 32 pages. |
| 2. | a book of this size. Symbol: 16mo, 16° |
| 3. | printed, folded, or bound in sixteenmo; sextodecimo. |
| sex·to·dec·i·mo (sěk'stō-děs'ə-mō') n. pl. sex·to·dec·i·mos In both senses also called sixteenmo.
[Latin sextōdecimō, ablative of sextusdecimus, one sixteenth : sextus, sixth; see s(w)eks in Indo-European roots + decimus, tenth (from decem, ten; see dek  in Indo-European roots).] |
| six·teen·mo (sĭk-stēn'mō) n. pl. six·teen·mos See sextodecimo. |
moʊ