What is the opposite of -ectasis?

The opposite of "-ectasis" depends on the context. "-ectasis" is a suffix that means "dilation" or "expansion".

Here are some examples:

* Bronchiectasis: Dilation of the bronchi. The opposite would be bronchiostenosis (constriction of the bronchi).

* Gastrectasis: Dilation of the stomach. The opposite would be gastric constriction or gastric narrowing.

* Mydriasis: Dilation of the pupil. The opposite would be miosis (constriction of the pupil).

Therefore, the opposite of "-ectasis" is generally "-stenosis" (constriction) or "-constriction" (narrowing).

However, depending on the specific word, the opposite may not be a single word. It could be a phrase describing the opposite action or state.