Watergaw.

My wife and I are watching the tenth season of Shetland (and looking forward to the eleventh, while mourning the recently announced departure of lead actress Alison O’Donnell), and I was delighted to see that one of the characters, a craggy and mysterious poet named Ed Tulloch, runs a pub called The Watergaw. After the show I read her the Hugh MacDiarmid poem of that name (which I’ve loved for over half a century now), and then I thought I’d investigate the word, which turns out to be not only interesting in itself but tangled up in the history of the poem. The OED entry (revised 2015) says: 1. A secondary or imperfectly-formed rainbow; (more widely) any of various phenomena in the clouds and sky that are believed to be portents of approaching rain. Also in extended use. regional in later use (now chiefly Scottish). Cf. weather-gall n [“An imperfect rainbow, believed to be a presage of storm”]. 1573 Like as a rocke that from a loftie mount doth headlonge fall, Enforst with rage of…