Login or register (free and only takes a few minutes) to participate in this question.
You will also have access to many other tools and opportunities designed for those who have language-related jobs (or are passionate about them). Participation is free and the site has a strict confidentiality policy.
Reference information: I have been researching this term myself and have come up at least with an explanation in Spanish of what this is, leading me to believe that the correct answer is not "pigeon-hole".
"Tabicón conejero. En él, los ladrillos de una misma hilada van separados entre sí, dejando huecos entre ellos para aligerar el conjunto y permitir la ventilación. Se utiliza generalmente para la formación de pendientes en las cubiertas". There's a picture if you click on the link.