I would use these resources for moments when I think I need to zoom out. I need a definition, a refresh on a debate, some broader themes. Think of these articles as scholarly Wikipedia entries.
Updated quarterly. Covers words from across the English-speaking world and offers etymological analysis, listings of variant spellings, and phonetic pronunciation. Corresponds to the print Oxford English Dictionary published in 1989 and the three Additions volumes published 1993-1997.