1 [uncountable and countable]
the main ideas or facts about something, without the details:
a research proposal outline
an outline of world history
a broad outline of the committee's plans
A debt reduction scheme was agreed in outline (=people agreed on its main points).
2CF [uncountable and countable]
a line around the edge of something which shows its shape
The outlines of animals were cut into the rock.
an outline map of Europe
figures drawn in outline
a plan for a piece of writing in which each new idea or fact is separately written down:
Always write an outline for your essays.