characteristic note
The one note that separates a mode from plain major or minor, the note that makes it that mode.
The single note that separates a mode from plain major or minor, the one that gives it its flavor. Dorian is minor plus a natural 6th, Lydian is major plus a sharp 4th, and so on: find that note and you have found the mode. Experienced players place it with care, since leaning on it too hard turns a mode into an exercise.
Learn it: Modes
The one-sentence definition at the top is the same one the Theory Aide extension shows as a tooltip inside Ableton Live. Hover any dotted term for its own.