Proper citation of equations in scientific papers - terminology
From Higham, Handbook of writing for the mathematical sciences (emphasis mine):

Referencing Equations
When you reference an earlier equation it helps
the reader if you add a word or phrase describing the nature of that
equation. The aim is to save the reader the trouble of turning back to
look at the earlier equation. For example, &quot;From the definition (6.2)
of dual norm&quot; is more helpful than &quot;From (6.2)&quot;; and &quot;Combining the
recurrence (3.14) with inequality (2.9)&quot; is more helpful than
&quot;Combining (3.14) and (2.9)&quot;. Mermin [200] calls this advice the &quot;Good
Samaritan Rule&quot;. As in these examples, the word added should be something more informative than just &quot;equation&quot; (or the ugly abbreviation &quot;Eq.&quot;), and inequalities, implications and lone
expressions should not be referred to as equations.

Pro-tip: arguing with a referee on such trivialities is rarely worth your time. Just do what they suggest.