What is the explicit meaning of “corresponding author”?
IEEE distinguishes between contact author and corresponding author:

Contact Author: This is the person who is contacted in regards to the submission during the peer-review and production processes.
Corresponding Author: This is the person who is listed as the author to be contacted in the printed publication.

PLoS states two types of corresponding authors:

Please note that the corresponding author for the online submission process can be different from the corresponding author of your published manuscript.

Copernicus uses the terms contact author and corresponding author:

From submission to publication, the authors of a manuscript are formally represented by the registered contact author(s). After publication, the authors of a manuscript are formally represented by the corresponding author(s) specified in the published paper.

Personally, I've seen this differentiation several times. Sometimes the corresponding author is simply a role in the journal system that the submitting author/person can assign to one of the authors during the submission process. The corresponding author might also change during the process.
Conclusion:
Some publishers make a difference between the author corresponding with the journal (submitting/contact author) and the author corresponding with potential readers of the article (corresponding author). Some publishers don't. It's absolutely inhomogeneous and seems also to vary by journal not only by publisher. And it varies over time.

Side note:
And yes, these publishers are indexed in SCOPUS and Web of Science (Science Citation Index, Thomson Reuters Master Journal List).
Search for the publishers in SCOPUS (select checkbox &quot;publisher&quot;) or the Thomson Reuters Master Journal List (TRMJL). The latter includes all journals indexed in Web of Science. Unfortunately, the search in TRMJL is only based on journals and not on publishers. Search for &quot;plos&quot; to see PLOS journals, &quot;ieee&quot; for IEEE journals and e.g. &quot;geoscientific&quot; to see two Copernicus journals. See also IEEE indexing agreements, Visibility of PLoS and Copernicus metrics.