What is Clean Price?

Legal Definition
In finance, the clean price is the price of a bond excluding any interest that has accrued since issue or the most recent coupon payment. This is to be compared with the dirty price, which is the price of a bond including the accrued interest.

Clean Price = Dirty Price - Accrued Interest

When bond prices are quoted on a Bloomberg Terminal or Reuters they are quoted using the clean price. The clean price is mostly quoted in the US bond markets. Given the quotes, traders tend to think of bonds in terms of their clean prices.

Clean prices are more stable over time than dirty prices – when clean prices change, it is for an economic reason, for instance a change in interest rates or in the bond issuer's credit quality. Dirty prices, on the other hand, change day to day depending on where the current date is in relation to the coupon dates, in addition to any economic reasons.
-- Wikipedia
Legal Definition
Securities market term. A price of a bond that excludes the interest accrued on the bond. Price et al is quoted and documented. However, a buyer must pay the quoted price plus the accrued interest, called the dirty price, to purchase the bond. Prominent in the UK and elsewhere, but not in the US.