In this article, I will be explaining the difference between a dimension and a metric.
A dimension is any kind of data that can be used to describe what you are tracking with words.
Examples include:
Device type, browser, browser version
Vendor, program, campaign
Country, city, language
A metric is data that has a numerical value. A metric is anything you can count.
Examples include:
Bounce rate, intent rate, visitor count
Conversion rate, number of pages

In this table, Device and Country are both dimensions because they do not have a numerical value. Bounce Count and Visit Count are metrics because the data is countable.