* A specialized or proprietary term: A particular company or project might have used this term to describe a specific type of buttress designed to interface with a lip or projection on another structural element.
* A descriptive term: It could be a less formal, descriptive way of talking about a buttress that is shaped or positioned to provide support to a feature that has a lip or edge. The lip or edge may be a part of the wall to be supported, or it may be a feature such as a cornice or balcony.
* A typo or misunderstanding: There's a slight chance it's a misspelling or misinterpretation of another term.
To understand what it means in a specific context, you would need more information about where you encountered the term.
If you can provide the source where you found this term, I may be able to give you a more specific and accurate explanation.