The story
From the mathematical formula (∂vomma)/(∂σ), the partial derivative of vomma with respect to volatility (σ), pronounced as "D vomma (by) D vol(atility)".
Etymology from Wiktionary, CC BY-SA 4.0.
DvommaDvol
Today it means: A third-order measure of derivative price sensitivity, expressed as the rate of change of vomma with respect to changes in the volatility of the underlying asset. Full definition →