Plural of applicability; multiple instances or contexts in which something is applicable or can be applied.
From 'applicable' (from Latin 'applicabilis') plus '-ity' (suffix forming abstract nouns from adjectives) plus '-ies' (plural). A compound chain of suffixes creating a plural noun.
Using 'applicabilities' (plural) is rare but precise—it suggests a thing has multiple different ways it can be applied, not just whether it's applicable in general!
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