meg·a·vi·ta·min 
(mĕgə-vī′tə-mĭn)
(mĕgə-vī′tə-mĭn)n.
A dose of a vitamin greatly exceeding the recommended daily allowance.
- high beam
- highbinder
- high blood pressure
- highborn
- highboy
- highbred
- highbrow
- highbrowism
- highbush blueberry
- highbush cranberry
- highchair
- High-Church
- high-class
- high comedy
- high command
- high commissioner
- high-concept
- high-count
- high court
- high-def
- high definition
- high-definition
- high-density lipoprotein
- high-density polyethylene
- high-end