By Chinua Asuzu
Caselaw (case law is permissible) is a mass noun and shouldn’t be pluralized.
It’s not a count noun.
Caselaw means the “law to be found in the collection of reported cases that form all or part of the body of law within a jurisdiction.” Black’s Law Dictionary, 11th ed. (Thompson Reuters, 2019), 267.
The word “caselaws” and the phrase “case laws” are not only bad English but also bad law.
Even Microsoft Word winces at “caselaws.”
Conceivably, the plural form might pass muster when speaking of several jurisdictions.
