twin·ning 
(twĭnĭng)
(twĭnĭng)n.
1. The bearing of twins.
2. A pairing or union of two similar or identical objects.
3. Mineralogy The formation of twin crystals.
- hyperbolical
- hyperbolically
- hyperbolic function
- hyperbolic paraboloid
- hyperbolism
- hyperbolize
- hyperboloid
- hyperboloidal
- Hyperborean
- hypercalcemia
- hypercapnia
- hypercatalectic
- hypercatalexis
- hypercharge
- hypercholesterolemia
- hyperconscious
- hypercorrect
- hypercorrection
- hypercorrectly
- hypercorrectness
- hypercritical
- hypercritically
- hypercriticism
- hypercube
- hyperdrive