(physics) An electron ejected by recoil when a rapidly moving alpha particle or other charged particle passes through matter.

plural of delta glider

a gliding aircraft with a delta wing

(chemistry) A notation for denoting the prevalence of an isotope, equal to the normalized ratio of one isotope to another in a sample relative to that same ratio in a standard.

plural of delta iron

(finance) A second-order measure of derivative price sensitivity, expressed as the instantaneous rate of change of delta with respect to time.

One of 64 counties in Colorado, United States. County seat: Delta. Named after the county seat, which is situated on a delta.

(finance) A measure of derivative price sensitivity with respect to changes in the correlation between the underlying assets in a multi-asset option.

(behavioral psychology) A stimulus that does not reinforce an existing behavior in a subject and causes the subject to employ a new behavior.

The highly virulent B.1.617.2 strain of the SARS-CoV-2 virus that causes COVID-19.