Definition from Wiktionary, the free dictionary
See also Vega
Perhaps chosen arbitrarily as a word beginning with "v" (for "volatility") that sounds as if it could be a Greek letter (like the related risk parameters "delta", "gamma" etc.)
vega (plural vegas)
- (finance) A measurement of the sensitivity of the value of an option to changes in the implied volatility of the price of the underlying product.
Derived terms 
- vega þungt (to carry a lot of weight)
- vega upp á móti (to counterbalance something, to compensate for something)
- vega salt
- vega sig upp (to pull oneself up)
Old Norse 
Etymology 1 
- Plural form of vegr, ‘ways’
- (poetic) earth
- Hvé sú jǫrð heitir, / er liggr fyr alda sonum / heimi hverjum í?
- [...] Jǫrð heitir með mǫnnum, / en með Ásum fold, / kalla vega Vanir. — verses 9 and 10 of the Alvíssmál
- How is the earth named, / that which lies before the sons of men, / in each of the worlds?
- [...] "Earth" it is named among men, / but among the Æsir "Field", / the Vanir call it "Ways".
Etymology 2 
- to weigh
vega f (plural vegas)
- fertile lowland
- grassy plain
- valley (the fertile lowlands surrounding a river)
- alluvial plain