sediliaPronunciation: /sɪˈdɪlɪə/Definition of sedilia noun (singular sedile /sɪˈdʌɪli/) a group of stone seats for clergy in the south chancel wall of a church, usually three in number and often canopied and decorated. Origin: late 18th century: from Latin, 'seat', from sedere 'sit'sedilia in other Oxford dictionaries Definition of sedilia in the US English dictionary