Definition:
Consistency is about making elements uniform and giving equal priority to the two or more.
Consistent having the same look and behave in the same way.
Examples:
Figure: Showing consistent web design in all devices
Figure: Consistent font, color and graphic for a logo
Figure: Giving equal priority for the both making consistent
Figure: Maintained consistent for "How we can help" and "Information and support"
Conclusion:
1). If we show or compare two or more objects then we should maintain consistency for showing that objects.2). Here consistent means if we give 4 different kind of differences for one object, then for second object also we need to give the same type of 4 differences.