This is a task for a new cool feature.
Wiktionaries offer some definitions but there are many ways to describe a meaning, and the actual wiktionary interface doesn't make it easy to display definitions from other dictionaries, definitions that define the same word with a different method or at a different epoch. Some dictionaries are mentioned as references but they are not accessible in Wiktionary.
Many dictionaries are in plain-text in Wikisource and can serve to offer more definitions. A dedicated transclusion may help harvesting automatically entries with a specific tagging in the dictionaries hosted in Wikisources. They could come from several Wikisources, to be display in several Wiktionaries. Some dictionaries are already properly tagged; for the others, it could be a good opportunity to do it, so that they can more easily be reused in open source projects.
It could be a new tab next to "Article" and "Talk", named "Dictionaries" with a list of definitions from several sources. It could be automatized or update manually, as there is not some much new dictionaries in Wikisource. This feature could shed light on Wikisource importance for archiving old resource and bring Wiktionary to a next level, moving from one dictionary to an extended dictionary with the historical sum of previous lexicographic works.
This suggestion has been posted in Community Wishlist Survey 2020, ended 16th with 34 votes.