sweetener

n. something that sweetens; added incentive

A sweetener is a food additive which adds the basic taste of sweetness to a food. In Commonwealth English, "sweeteners" is usually used to refer to sugar substitutes.
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Noun
1. something added to foods to make them taste sweeter
(synonym) sweetening
(hypernym) flavorer, flavourer, flavoring, flavouring, seasoner, seasoning
(hyponym) aspartame
(derivation) sweeten, dulcify, edulcorate, dulcorate
2. anything that serves as an enticement
(synonym) bait, come-on, hook, lure
(hypernym) temptation, enticement
(derivation) sweeten

(n.)
One who, or that which, sweetens; one who palliates; that which moderates acrimony.
  

A feature of a security which makes it more attractive to potential purchasers.