I saw this come up in another question in regards to drinking a healing potion not being a Use an Object action as the text in the equipment chapter under healing potion specifically says that using a healing potion is an action.
But if I look at the other objects in the equipment chapter, I find similar text:
Applying the poison takes an action.
Drinking or administering the potion takes an action.
As an action, you can spread a bag of caltrops...
None of these refer specifically to Use an Object.
However, the Use an Object text in the Combat chapter says this.
When an object requires your action for its use, you take the Use an Object action.
So the text in the Combat chapter, by my reading, seems to say that the 'action' in the text of specific objects in the equipment section is Use an Object.
Is this correct? Is using any of the objects in the equipment chapter the Use an Object action as the Use an Object text seems to say? If not, then what can you do with Use an Object?