A Google-produced definition of physicochemical meaning of or relating to physics and chemistry or their overlapping joint subject of physical chemistry.

In terminology, physicochemical (TR=27) or "physico-chemical", not to be confused with physiochemical (physiological chemistry or chemistry of physiology), refers to physical chemistry or physical chemical phenomena.

The term “physico-chemical” tended to be used in the years circa 1870s to 1930s, after which the term “physical chemistry” tended to supersede the former; although not completely (the unwieldy phrase “physical chemical”, e.g., is inept in certain uses). The the following Google-made term usage chronology outlines this:

Adams
The following are ripe quotes employing the term "physico-chemical" by American physical humanities historian Henry Adams:

“On the physico-chemical law of development and dynamics, our society has reached what is called the critical point where it is near a new phase or equilibrium.”

— Henry Adams (1908), “Letter to Charles Gaskell” (Sep 27) [1]

“I’m looking for a ‘young and innocent physico-chemist [see: Henry Bumstead] who wants to earn a few dollars by teaching an idiot what is the first element of theory and expression in physics.”

— Henry Adams (1908), “Note to John Jameson” (Dec) [2]

“My essay ‘The Rule of Phase [Applied to History]’ is a ‘mere intellectual plaything, like a puzzle’. I am interested in getting it into the hands of a ‘scientific, physico-chemical proofreader’ and I am willing to pay ‘liberally for the job’.”

— Henry Adams (1909), Notes to Brooks Adams and John Jameson [1]

Quotes
The following are other noted quotes:

“To a materialist no thing is real but atoms in a void and we are but molecular people controlled by the actions of natural physicochemical law.”

— George Scott (1985), “Molecular People” dedicated to Lucretius

See also
● Physicochemical humanities

References
1. (a) Adams, Henry. (1908). “Letter to Charles Gaskell”, Sep 27.
(b) Samuels, Ernest. (1989). Henry Adams (physico-chemical, pgs. 401, 411). Harvard University Press.
2. (a) Adams, Henry. (1908). “Note to John Jameson”, circa early Dec.
(b) Samuels, Ernest. (1989). Henry Adams (pg. 409). Harvard University Press.

External links
● Physicochemical – Wikipedia.