An emphasis/concentration is to pick a specialty within a major. For example, you can declare a major in business and a concentration in accounting. You’ll take the “normal” required classes for a business major, but then you’ll also be required to take a few extra classes that focus specifically on accounting such as audit procedures, taxation, or cost accounting.
Keep in mind that every school is different as to whether an emphasis/concentration is required, so check the school’s requirements! If it’s not required to declare one now and you’re not positive which emphasis/concentration you are interested in, it’s recommended that you not declare one right away. Use the first two years to take your general education requirements within your major and see what topics you like within your major before putting yourself on a specific concentration path.
The sooner you declare a major and/or an emphasis/concentration, the better you are able to plan out your academic career to ensure you graduate in 4 years. At most colleges, taking 12 credits is considered full time, but you can take up to 18 credits without paying additional tuition charges. Registering for at least 15 credits each semester should increase the odds of being able to graduate in 4 years. You do not want to go any longer than necessary!