Parashas Shemos · Passuk 1:11
Chabad.org — English translation + Rashi
Torah Temimah points to Sotah 11a (verified).
Sefaria — Exodus 1:11
Sefaria — Sotah 11a
E-Daf — Sotah 11a
English: Rav and Shmuel disagree about the names Pithom and Raamses. One says Pithom was the true name and Raamses describes the buildings collapsing as they were built; the other reverses the names and explains Pithom as “the mouth of the abyss,” which swallowed each new construction.
In context: See the cited source for the full section.
Custom — dual etymology of the city names.
The store-cities were constructed so that the work could never be completed; each portion that was built immediately failed.