In physical chemistry, "A" is the symbol for affinity, chemical affinity, or elective affinity.
Arbeit | Work
In thermodynamics, "A", in some publications, refers to mechanical "work", from the German “Arbeit”, meaning work, and or to Helmholtz free energy, a thermodynamic formulation of affinity.
- Thims, Libb. (2020). Human Chemical Thermodynamics — Chemical Thermodynamics Applied to the Humanities: Meaning, Morality, Purpose; Sociology, Economics, Ecology; History, Philosophy, Government, Anthropology, Politics, Business, Jurisprudence; Religion, Relationships, Warfare, and Love (§2: Alphabet) (pdf). Publisher.