My cat is mainly white with black spots, but he does have a light brown 'goatee' going on, along with light brown spots next to the black spots and a large one at the base of his tail and inside of his leg. Where the black and brown meet it mixes together, but not completely, and there are hints of brown throughout some black spots in a semi stripe pattern. I've tried reading standards about calico coat colors and nothing really classifies him. Sadly, I can't add a photo.
What is a calico cat?
A calico cat has orange or cream fur and black or gray fur in large distinct patches, with the rest of its body being white. The white might just be on the belly, or it might cover the majority of the body, with just a few colored patches on the back, tail, and face.
But there are also tortoiseshell cats.
Tortoiseshell cats are very similar to calico cats in that they have both orange/cream fur and black/gray fur, but unlike the calico cats, the areas of color aren't in distinct patches, rather the colors are intermixed either in little patches, or even just all mixed together.
Genetically, calico cats and tortoiseshell cats are the same. The difference in their looks is due to how they happened to develop in the womb.
Is your cat a calico or tortoiseshell cat?
Almost certainly not.
The reason I say this is because your cat is male, and calico and tortoiseshell cats are almost always female. The reason for this is that the gene for their coat color is on the X chromosome, and what usually determines a cat's sex is having two X chromosomes, whereas male cats usually have an X and Y, just like with humans. The black/gray gene is a separate gene from the orange/cream gene, and so normally the two colors can only be present on the cat if it has two X chromosomes.
But rarely there are exceptions.
Very rarely something unusual happens in the cat's development in the womb where a cat developed as a male, even though it somehow has genes for both colors. This can happen in a variety of ways, such as the cat actually ended up with three sex chromosomes (XXY, also known as Klinefelter syndrome), or sometimes two genetically distinct embryos merge during development into one, and the one resulting embryo still has cells of both embryos (that is, a genetic chimera), or just a random mutation happened.
In conclusion, while it is possible your male cat is a calico or tortoiseshell, it's extremely unlikely. Furthermore, since such a thing is unusual enough I would expect your vet to mention it, especially since at least some of the conditions that male cats end up as calicos, such as Klinefelter syndrome, can lead to other health problems, and so I would expect a vet to want to investigate that it does not have any of these problems.
However, at the same time, it's still not impossible. To be honest, I find it hard to picture how the cat looks from just a written description, so I don't think I could say for certain without seeing the cat.