Title page of Daniel Bernoulli's 1738 Hydrodynamica.

In famous publications, Hydrodynamica is a 1738 book by Dutch-born Swiss physicist Daniel Bernoulli in which, in large part, the definition of pressure was introduced along with the basics of the ideal gas law and the kinetic theory. [1]

References
1. (a) Bernoulli, Daniel. (1738). “On the Properties and Motions of Elastic Fluids, Especially Air” (Hydrodynamica, Section 10) in: The Kinetic Theory of Gases of Gases (pgs. 57-65), 2003, by Stephen G. Brush, Nancy S. Hall. Imperial College Press.
(b) Bernoulli, Daniel. (1738). Hydrodynamica, Sive Vivibus et Motimus Fluidorum Commentarii. Sectio Decima: “De affectionibus atque botimus fluidorum elasticorum, praecipue autem aeris.” (pgs. 200-204). Argentorati, Sumptibus Johannes Reinholdi Dulseckeri.