English to Portuguese Tech/Engineering IT (Information Technology)

The context is a little limited, so I am struggling to understand the meaning of outline here. It is an instructional document, and these terms do not appear to the end user, which makes me think that it may be related to icons, instead of something like a general view, but I would like to make sure if this line of thought is correct here. Here is the list of items with the term "outline" in no particular order:

Clock Outline
Questions Outline
No Phones Outline
Laptop Outline
Classroom Outline