biennial.net
Dozens of cities run one. Venice, São Paulo, Berlin, Istanbul, Sharjah, the Whitney. They take years to organise, move enormous amounts of money and attention, and there is no central place covering them.
That gap is the opportunity. A listings and calendar site, a criticism platform, a database of past editions and participating artists, or a travel resource for people who plan their year around these events. All of them would be useful and all of them fit this name exactly.
The word has a plain meaning outside art as well, covering anything on a two-year cycle: trade shows, conferences, statutory reports. That broadens the buyer pool without diluting the primary reading.
The .net works because the audience is international and arrives through search, links and word of mouth. What matters is that the name is the word for the thing.
Single dictionary word, listed now. Enquiries welcome.