The term 'eyebrow shapes' can refer to the various ways in which eyebrows can be groomed and shaped. One of the most common eyebrow shapes is arcs, which is a four-letter word that can be used to solve a crossword puzzle. Arcs are curved lines that are used to shape the brows, creating a more symmetrical look. Other eyebrow shapes include straight lines, angled lines, and even more intricate designs.