Cannibalisation refers to competition within your own product-line causing a reduction in revenue. E.g. with simple figures: Apple spend 1 billion producing iP

Cannibalisation refers to competition within your own product-line causing a reduction in revenue. E.g. with simple figures: Apple spend 1 billion producing iPads from start to finish, and selling them produces 10b in income. They then introduce Macbooks which cost 5b to produce and result in 10b in income. If the introduction of lower margin Macbooks causes a 25% drop in sales of higher margin iPads, then the profitability of their product line has been reduced due to inter-product competition. It's generally not a good thing and represents a waste of resources.