Does 5e use any terminology for something you get to do for free?

I think "Free action" used to be the term in 4e but can't find an equivalent for 5e.

In the physical Player's Handbook it is p.190 in the Combat section.

"Other activities on your turn" and the additional rules box "interacting with objects around you".

In 5e this is much less codified than in 4e.

It's mostly under a "free object interaction".

Which is a bit of a misnomer, because it's limited to one per turn, so it's just as much part of your action economy as your other actions, but still.

There isn't really anything you get to do for free. You can only do things so many times (usually once, but exceptions abound), then you can't do them any more until your turn/the round ends and a new one begins.

No discrete term, no.

We usually call it the free interaction or free object interaction, because it is limited to interacting with a single object (usually drawing/stowing weapons), and it has to be tracked since you specifically only get 1 of this barely named thing.

Things like talking, etc is just completely free and doesn't need tracked.

Below is what I have so far. Would you guys agree it work with how WotC would word the item?

Reminiscent of a collection of sawbones’ syringes, this apparatus administers an elixir of the of the wearers choice after sustaining an injury. 

When your hit points are equal to or less than half you consume the potion contained within as a free action as if you had spent an action to do so. 
 
Once the potion within has been consumed it must be replaced. It takes 1 minute to fill or decant the potion contained within the Auto-Injector 

Quote from Mikaos >>

Below is what I have so far. Would you guys agree it work with how WotC would word the item?

 

Reminiscent of a collection of sawbones’ syringes, this apparatus administers an elixir of the of the wearers choice after sustaining an injury. 

When your hit points are equal to or less than half you consume the potion contained within as a free action as if you had spent an action to do so. 
 
Once the potion within has been consumed it must be replaced. It takes 1 minute to fill or decant the potion contained within the Auto-Injector 

 Nope, this isn't in line with normal D&D terminology as there is no such thing as a 'free action'. It would/could/should be phrased as:

Reminiscent of a collection of sawbones’ syringes, this apparatus administers an elixir of the of the wearers choice after sustaining an injury. 

When your hit points are equal to or less than half you consume the potion contained within, no action required
 
Once the potion within has been consumed it must be replaced. It takes 1 minute to fill or decant the potion contained within the Auto-Injector 

Auto-Injector

Here is a lick to the final item.