PLAIN-LANGUAGE DEFINITION
Aspect ratio
Aspect ratio is the relationship between a frame's width and height.
IN PRACTICE
An example
A 1080 by 1920 image has a 9:16 portrait aspect ratio.
What this does not tell you
Matching the ratio does not guarantee adequate resolution or safe text placement.
Use the term precisely
When you use this term in a brief or report, include the relevant source, scope and assumptions. An example explains the concept; it is not a benchmark or a promise of results.