brim

Brim refers to the projecting edge or lip of an object with circular or curved geometry. In everyday use, it most commonly denotes the edge of a hat or cap, the part that shades the eyes. Brims vary in width, stiffness, and shaping, from the wide, floppy brim of a sun hat to the stiff, structured brim of a fedora.

It is also used for the upper edge of a container or vessel, such as the brim of a cup or bowl, though in many technical contexts the term rim is preferred. As a verb, brim means to fill to the top or to be full at the edge, as in a cup that brims with water.

Origin and usage: Brim is common in everyday speech and describes both physical edges and fullness. The word "brim" contrasts with "rim," a more general edge term used in technical or geometric contexts. Derived forms include brimmed, brimful, and brimming.