Think of a Siamese. It has a lanky, slender build. with a longer face and large ears. They have a very harsh voice, a tendancy to talk a lot, and they get very attached to their chosen person. An Oriental Shorthair is a Siamese without the color-point markings. It is a quirk of cat genetics that a pure Siamese that mates with a cat with no siamese will usually have solid black kittens. Many (but not all) black cats will have some Siamese ancestry. Color-point markings are recesive, and can show up down the line if two part siamese get together. My second cat, Tayla, was black with some white on her. If you looked at her like a domestic shorthair, her hear was too big for her body, her ears too big for her head, and she was Roman-nosed. She had a sleek close-lying coat, and a slender tail. In other words, she had the body of a Siamese. She also had a voice that sounded like you left her out in the rain and it rusted. She did NOT have the tendency for conversation, thank goodness! The Oriental Shorthair type that I trapped looked exactly like a Siamese except with grey tiger stripes all over. She had a slightly strident voice, she loved to talk to me, and she claimed me as her own.
