There are two kinds of English-English dictionaries: dictionaries for learners and dictionaries for native speakers. Dictionaries for native speakers are used by Americans, Britons, etc. to look up rare words, such as inextricable ____ tintinnabulation. Dictionaries for learners are used by people who are learning English as a second language.
As for the usage of coordinating conjunctions, which one fits the blank space better? I prefer “or” because it suggests that there are many more possibilities than the two mentioned. However, some may claim that here "and" is more fitting because "such as" introduces a category of words that one might want to look up, and the two examples belong together in that category. (I know that both are grammatically correct. I'd like to ask about your preference. )