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-dad, -tad Suffix used to form abstract nouns from adjectives.
From Latin -tatem, accusative of -tas 'id.' From Proto-Italic *-tāts 'id.' From Proto-Indo-European *-teh2ts 'id.'
Indo-European
Romance
Asturian -tá, Portuguese -dade, Galician -dade, Catalan -tat, French , Italian -ità, Aromanian -tati, Romanian -tate
Hellenic
Ancient Greek -της (tes)
Indo-Iranian
Sanskrit -tāti