The ensuing discussion and additional reading shows that the delineation in usage between the terms "phenotype" and "morph" is not always clear cut.
An organism's phenotype results from two basic factors: the expression of an organism's genetic code, or its genotype, and the influence of environmental factors. Both factors may interact, further affecting phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. [Source]
According to the above, morphs would be clearly different phenotypes.
However, the difference in fur colouring in dog morphs is solely the result of the genotype and not at all the environment.
Biston betularia caterpillar phenotypes on, respectively, birch (left) and willow (right), demonstrating a colour polyphenism as a result of its environment and diet.
Whereas the dark-morph or melanistic jaguar does not result from an adaptation to its environment or diet.