- The practice of having sex involving three participants, i.e. threesomes.
- "Troilism is an unusual practice."
- "The woman wants to censor us, Hill. If she had her way, all we'd show would be Andy bloody Pandy, and she'd stop him climbing into that basket with Looby Lou - let alone Teddy - lest some child be corrupted by the whiff of puppet troilism. And bestiality, I suppose - or would it be bestiality with a teddy bear... rather than a real bear?" - Sir Hugh Carleton Greene, portrayed by Hugh Bonneville in Filth: The Mary Whitehouse Story, on his exasperation at Mary Whitehouse's (Julie Walters) attempts to remove any material deemed mildly offensive from BBC TV.