The Accusative case is for specific direct objects. It appears on many things that are the objects of verbs and have the word "the" in English. You can read more about how to form it here: https://www.duolingo.com/comment/9041808
They should definitely be in the keyboard dictionary (if you are talking about something like autocorrect). Otherwise, if it is a normal dictionary, you will only find words in the nominative case, which is true of most dictionaries for languages with cases.