Where does the C# generics naming convention come from?

I understand T c开发者_JAVA百科omes from Type, but why is it that the next variable often used is K?

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I've seen K used for Key but not frequently as the "next" type parameter. For example, you'll see

Dictionary<K, V>

where K is for Key and V is for Value.

Sometimes you'll see T1, T2, etc. or T, U, V (the former is preferred here). But I prefer more descriptive names like

Map<TSource, TDestination>

or

Create<TUnitOfWork>

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My guess would be that it's from Key.

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One more variation is the GenericFunction<T1,T2,TResult>, where TResult is the type of value returned by the functon. (as in, Func<T1,T2,...,TResult>)