What is the term for the cannibalization of one tax by another? The context for the question is a situation where a government-owned lottery pays corporation tax, but an additional betting duty levied on individual gamblers reduces the lottery's profits, thereby decreasing the amount of corporation tax received by the State.
In this case we would say that duty levied on the lottery would erode the tax base for corporate tax. However, you should note that eroding tax base is a general term that can be applied to any action that decreases the taxable income/wealth/economic activity. But I dont think there is any more specific word in economic jargon just for that.