Does milk dilute the strength of a coffee cup? meaning can adding more milk weaken coffee?

Not really: If you start out with a cup of coffee and add a cup of milk and then drink the whole thing, you have still drank a whole cup of coffee. It only works if you add less coffee and make up the difference by adding milk.

It depends on amount: Yes it does and the dilution depends on the proportion of milk to coffee, if you are putting half cup of coffee and half cup of milk it is diluted 50%,compared to black coffee and no milk,that is 100% coffee Also depends on how you make coffee,ie' how many cups of coffee to how much water.That is the strength of black coffee There are many factors taken into consideration for strength of Coffee