from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Arranged or occurring in pairs; twin.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Twin, twinned; growing or occurring in pairs.
from the GNU version of the Collaborative International Dictionary of English
- adj. Growing in pairs or twins.
from The Century Dictionary and Cyclopedia
- In botany, twofold; twin; growing double, as the fruits of umbelliferous plants, the anthers of bedstraw, or the tubers of some orchids.
- In zoology, twain; paired: applied to two spots, spines, tubercles, etc., when they form a pair touching each other.
From Greek didumos, twin; see dwo- in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)
Modern Latin, from Ancient Greek δίδυμος ("twin"). (Wiktionary)