Explain xkcd: It's 'cause you're dumb.
If biannual is ambiguous, meaning either biennial (every two years) or semiannual (twice each year), then isn't sesquiannual similarly ambiguous, meaning either every 1.5 years (every 18 months), or 1.5 times a year (every 8 months)?
Pete (talk) 06:38, 11 November 2015 (UTC)