Oxford English Dictionary http://www.oed.com/ equator: OED Word of the Day http://www.oed.com/cgi/display/50077205?rss=1 Today's word from the OED has the following earliest quotation: c1391 CHAUCER Astrol. I. {section}17 The middel cercle..is cleped also the weyere, equator of the day. Oxford English Dictionary 2008-05-10 Word of the Day 50077205 equator: OED Word of the Day