The term “unitasker” is used in two different ways. In the first sense, it refers to an object with one function, such as a rice cooker. It is also sometimes used in reference to people, as a description for someone who only completes one task at a time. Some people view unitaskers unfavorably in certain situations, whether they are objects or people, with the implication that the ability to perform multiple tasks is vital.
In the sense of an object, a unitasker is designed to perform one very specific function, and it is typically incapable of doing anything else. Ideally, engineers design the item to be extremely good at what it does. A waffle iron, for example, can only be used to make waffles, but it tends to make waffles extremely effectively, justifying its existence as a unitasker. Other objects as varied as saddles and soap dishes can also be considered unitaskers.
Most people take exception to unitaskers in the kitchen more than anywhere else. This is because space in the kitchen is typically constrained, and a unitasker takes up more space than an item which can perform multiple functions. For example, a lemon zester is really only good for removing the zest of citrus fruits, while a rough grater, like a Microplane® grater, can zest citrus and grate a number of other things from chocolate to cheese, making it a more effective kitchen tool. This is especially true with unitasking appliances, which can rapidly eat up space in a crowded kitchen.
In the sense of a person, being a unitasker isn't necessarily such a bad thing. Many people have very different ways of working, and some people prefer to work on one thing at a time. This does not necessarily make them less efficient, as the ability to focus on one task at once may allow someone to complete the task extremely well and in a reasonably short amount of time. Unfortunately for many people of a unitasking inclination, many modern schools and workplaces are geared towards multitaskers, which can make life extremely frustrating.
If you happen to prefer unitasking, you may want to avoid job advertisements for things like “fast paced workplaces,” and you may want to make your working style explicitly clear in job interviews, especially if you have excellent references which indicate that your unitasking nature is an asset to the workplace. You may also want to reference it in resumes with comments which indicate that you have “an eye for detail” which stress the positive sides of being a unitasker. In a school environment, try to create a schedule structure which works well for you, and do not be afraid to ask for help from staff and instructors.