Panic disorder and Panic attack

Panic disorder noun - An anxiety disorder characterized by unpredictable panic attacks; the attacks are usually severe but brief.

Panic attack and panic disorder are semantically related In some cases you can replace phrase "Panic attack" with "Panic disorder", this phrases are similar.

Panic attack noun - A sudden attack of fear.

Panic disorder and panic attack are semantically related in anxiety attack topic. You can use "Panic disorder" instead a noun phrase "Panic attack".