The Dictionary of Old Norse Prose (ONP) is an online dictionary containing over 50,000 words derived from texts of Old Norse prose. Published by the University of Copenhagen, the project is ongoing as of 2020 with new words added regularly. The dictionary is searchable in a number of ways: by headword, text, manuscript, type of word, and numerous others. ONP makes it corpus data freely downloadable and has added information like the genre of text from which the word derives or whether it used in poetry or legal texts as well. Users can also view the words contained in particular texts or manuscripts and download that data for research purposes. When available, the ONP links to images of manuscripts and freely available editions of texts. Dictionary entries contain a list of sources in which the word appears in addition to its grammatical qualities.
Additionally, the project includes an expansive bibliography and has an active social media presence that offers a word-of-the-day feature.