## apparent (quantity)

https://doi.org/10.1351/goldbook.A00418
A term, indicated by a superscript ', which means that a process is not well known or that its value carries uncertainties which are not known, e.g. $$\Delta G^{\,\unicode{x26ac}}′$$ is the apparent standard Gibbs energy change. In the context of @P04418@ the word is used in a different sense; as a symbol for 'apparent' in this connection the use of subscript $$\varphi$$, as in $$Y_{\varphi }$$, is recommended. Other notations employed for this property include $$^{\varphi }X$$ and $$\varphi _{X}$$.
Source:
PAC, 1986, 58, 1405. (Recommendations for the presentation of thermodynamic and related data in biology (Recommendations 1985)) on page 1408 [Terms] [Paper]