Something that widens or makes broader, or a person who widens something.
From 'widen' (to make wide) plus the agent suffix '-er' (one who does something), creating a word for an agent or tool that widens.
Widener Library at Harvard was named after Harry Elkins Widener, a book collector who died on the Titanic, and the library was built to 'widen' access to books for everyone—it's one of the largest university libraries in the world.
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