What is meant by the spread duration for a floating-rate bond?

What will be an ideal response?

A floating-rate bond's price sensitivity will depend on whether the spread that the market wants changes. The spread is reflected in the quoted margin in the coupon reset formula. The quoted margin is fixed over the life of a typical floating-rate bond (or floater).

Spread duration is a measure used to estimate the sensitivity of a floater's price sensitivity to a change in the spread. A spread duration of 1.4 for a floater would mean that if the spread the market requires changes by 100 basis points, the floater's price will change by about 1.4%.