Tailoring’s definition could fill a whole dictionary by itself. A tailor is the artisan who fits and measures a customer (think Savile Row) For a garment to be tailor-made is to be cut, it has to be constructed and made-to-measure for the individual. Tailored is also a way to describe a garment that is more structured and precisely fitted; in haute couture you have tailleur (tailored, fitted) and flou (the more fluid, evening wear and drape).
Trapeze Lines were popularised by Christian Dior’s successor, Yves Saint Laurent in spring 1958, with his Trapeze Line collection that featuring dresses that flared from the fitted shoulder line. The trapeze line reinvented the A-Line, what had bee “most wanted silhouette in Paris,” with the same swing as its circus counterpart.