the untier of a knot

The sun was almost at zenith and the glare was dazzlingly intense.

There's no olive oil; will sunflower oil do? — I'll have to run that by the boss.

Modesty forbade Fanny to describe her fellow-passengers' travelling costumes, for they were all gentlemen; but she recommended her own and little Ada's outfits to the ladies: a balmoral skirt (' balmorality' raged in the New World as well as in the Old); as many calico dresses as possible (but you had to remove the hoops, she warned, for crinolines with stiffeners in them would hardly permit a lady to get through the door of a western stage-coach, much less sit at ease in it for eight hours at a stretch); waterproof cloaks ; huge sunbonnets, with voluminous green veils ; buckskin gloves and stout, calf-length boots.