In software testing, code coverage is a measure of how many lines of code are tested (covered) by automated tests. This definition is precise and disambiguous.
However, there is an alternative definition:
Test coverage is a measure of how much of the feature set was executed as a result of a test.
This alternative definition focuses on specific features and counts how many features are covered by the test. This is sometimes referred to as the "happy path" because it only reflects what the user is expected to do, as opposed to the reality of what they will do with the website or mobile app. It is very hard to measure how adequately the listed "features" reflect actual features of the software, so it is difficult to quantify the test's effectiveness.
When talking about "test coverage," always clarify the definition of the phrase to ensure everyone is on the same page.