Jack Youngerman, a French-trained American artist whose profuse invention of abstract shapes in two and three dimensions opened up a new aesthetic vocabulary in the period immediately after Abstract Expressionism, died on Wednesday in Stony Brook, N.Y. He was 93.

Janet Goleas, his studio manager and archivist, said the cause was complications of a fall.

Mr. Youngerman, like many American artists in the late 1940s, studied in Paris on the G.I. Bill. Unlike them, he remained there, developing a distinctive style of abstraction based on organic shapes, drawing inspiration from the woodblock prints of Jean Arp and Wassily Kandinsky and, perhaps most decisively, the ink drawings of Henri Matisse.

Mr. Youngerman’s fluid, emblem-like shapes embraced flatness and frontal views, leaping forward to meet the viewer with bold primary colors. The shapes, vaguely floral or leafy, flirted with representation but remained aloof, floating like mysterious essences in a timeless spirit world.