Longman Dictionary of Contemporary English
Wiktionary
n. 1 Any carbonated, usually sweet, non-alcoholic drink. (qualifier: In this sense, juice, milk, tea and coffee are not soft drinks.) 2 (context broadly speaking English) Any non-alcoholic drink.
WordNet
n. nonalcoholic beverage (usually carbonated)
Wikipedia
A soft drink (see terminology for other names) is a drink that typically contains carbonated water, a sweetener, and a natural or artificial flavoring. The sweetener may be sugar, high-fructose corn syrup, fruit juice, sugar substitutes (in the case of diet drinks), or some combination of these. Soft drinks may also contain caffeine, colorings, preservatives, and other ingredients.
Soft drinks are called "soft" in contrast to "hard drinks" ( alcoholic beverages). Small amounts of alcohol may be present in a soft drink, but the alcohol content must be less than 0.5% of the total volume if the drink is to be considered non-alcoholic. Fruit juice, tea, and other such non-alcoholic beverages are technically soft drinks by this definition but are not generally referred to as such.
Soft drinks may be served chilled, over ice cubes or at room temperature. In rare cases, some soft drinks, such as Dr Pepper, can be served warm. Soft drinks are available in many formats, including cans, glass bottles, and plastic bottles (the latter in a variety of sizes ranging from small bottles to large 2-liter containers). Soft drinks are also widely available at fast food restaurants, movie theaters, convenience stores, casual dining restaurants, and bars from soda fountain machines. Soda fountain drinks are typically served in paper or plastic disposable cups in the first three venues. In casual dining restaurants and bars, soft drinks are often served in glasses. Soft drinks may be drunk with straws or sipped directly from the cups.
Soft drinks are mixed with other ingredients in several contexts. In Western countries, in bars and other places where alcohol is served (e.g., airplanes, restaurants and nightclubs) many mixed drinks are made by blending a soft drink with hard liquor and serving the drink over ice. One well-known example is the rum and coke, which may also contain lime juice. Some homemade fruit punch recipes, which may or may not contain alcohol, contain a mixture of various fruit juices and soda pop (e.g., ginger ale). At ice cream parlours and 1950s-themed diners, ice cream floats are often sold. Two popular ice cream floats are the coke float and the root beer float, which consist of a scoop of ice cream placed in a tall glass of the respectively named soft drinks.
Usage examples of "soft drink".
He would bring out grilled meat or fish and a country salad and some wine and a soft drink.
The thin synthetic fizz at least took away the taste of brick dust and cinders, though as usual I wished someone would invent a soft drink with a flavor of dry white wine.
It was wide and deep and dark, and composed of a popular soft drink, sweet and heady and very refreshing.