In the recently released (November 21, 2016) Unearthed Arana article, Cleric: Divine Domains, the Grave Domain ability Sentinel at Death’s Door has the following effect:
Any effects triggered by a critical hit are canceled.
My question is, are all effects that are triggered on a 20 of an attack roll considered critical effects? Or only effects that are called out as when a critical is made?
Consider the Sword of Sharpness (DMG, p.206):
When you attack a creature with this weapon and roll a 20 on the
attack roll, that target takes an extra 14 slashing damage.