how to distinguish and how not to get confused with each other.
The bigger word (mydriasis) is bigger pupil (dilated)
The shorter word (miosis) is smaller pupil (contracted)
To remember which drug is for what, optometrist gives atropine (anticholinergic) to dilate=mydriatic agent; therefore cholinergics (eg pilocarpine) are miotic agents.
Many mydriatics are also cycloplegics since cycloplegics are antimuscarinics (=anticholinergic)