From the locative of বিষয় (biśoẏ, “subject, theme”), with case ending -এ (-e).
বিষয়ে • (biśoẏe) (with genitive case)
- (generally with genitive) about, concerning
এ বিষয়ে সে একেবারেই বাচ্চা- e biśoẏe śe ekebarei bacca
- He is absolutely childish about this.