(By Matthew Baerman and Dunstan Brown): "This map shows instances of case syncretism in nominals (nouns, pronouns and adjectives). We identify case syncretism when a single inflected form corresponds to two or more case functions. The criterion used here for identifying case functions is form-based: a distinct morphosyntactic case is recognised for a language if it is ever correlated with a formal inflectional distinction (Comrie 1991: 44-47). For example, in Krongo, subject and object forms are never distinguished, so this is not construed as an example of case syncretism, but rather as a single nominative-accusative case (see (1)). However, the dative case is distinct in nouns but identical to this nominative-accusative form in pronouns, so a dative = nominative-accusative syncretism is recognised for Krongo."
This feature concerns case forms that coexpress ("syncretize") multiple meanings, and it specifies that the relevant meanings must be case meanings that are distinguished elsewhere in the language.