Flash of the Spirit

Wyatt MacGaffey (2016) says he coined 'cosmogram' in 1970, in talks with Thompson, for improvised ritual marks on the ground; Thompson popularised it. The diagram itself, he adds, is authentic.

Wyatt MacGaffey, 'Constructing a Kongo Identity: Scholarship and Mythopoesis', Comparative Studies in Society and History 58:1 (January 2016), note 21

Robert Farris Thompson's 1983 book on African art and philosophy in the Americas.

Sources2 sources

Primary source

Robert Farris Thompson, Flash of the Spirit: African and Afro-American Art and Philosophy, 1983, Kongo chapter, 'Tendwa Nza Kongo: The Kongo Cosmogram'Thompson's reading of the Kongo cosmogram and kalunga, the world of the dead, in Kongo graves and Black Atlantic art; his citations of Fu-Kiau Bunseki.
The bottom half of the Kongo cosmogram was also called kalunga

Scholarship

Wyatt MacGaffey, Constructing a Kongo Identity: Scholarship and Mythopoesis, Comparative Studies in Society and History 58:1, 2016, note 21MacGaffey coined 'cosmogram' in 1970 for improvised ritual ground-marks; Thompson popularised it; the diagram is authentic and current by the nineteenth century.
I began to use the word “cosmogram” in 1970 in discussions with R. F. Thompson