Furthermore, Microsoft Custom Translator service builds and makes use of its own general purpose dictionaries to improve the quality of its translation. You can think of the dictionary as a brute force 'copy and replace' for all the terms you list.
Dictionaries are sometimes called glossaries or term bases. Use a dictionary in your training, when you want Translator to translate any instances of the source phrase or sentence, using the translation you've provided in the dictionary. A dictionary is an aligned pair of documents that specifies a list of phrases or sentences and their corresponding translations.