Q:

A word describes things that can be used only once

I am wondering if there is a single word that describes things that can be used only once. My focus is links that usually sent to our emails in order to activate accounts or reset passwords. However, I do not mind to find a word for all kind of items that can be used only one time (e.g. Bullets, bombs, diapers, baby wipes, pads ... etc.

A:

Single-use 

adjective: single-use
1. designed to be used once and then disposed of or destroyed.
  "billions of single-use cups are thrown into landfill sites every year"   

The expression is also the de facto industry standard for that meaning.  

ISO 15223: Medical Devices and EN 980 cite that single use instruments or devices be labelled as such on their packaging with a universally recognized symbol to denote "do not re-use," "single use," or "use only once". This symbol is the numeral 2, within a circle with a 45° line through it. (WP)

A:

per @bye:
'Nonce' (nahnts) means "A word intended for a single use". A nonce word is a word which is created to suit a specific communication need, and which is not expected to be used again. It's not the technical term for that kind of link, but it is an excellent metaphor for it.
'Consumable' is used for things which have a distinctly finite number of uses. I don't think there is a widely used word that means specifically something which is single-use, although I might also suggest 'Ephemeral', meaning "Lasting for only a brief period; Transient"
I also think there is a case to be made for "Disposable". While it can refer to things which may optionally be disposed, it also refers to things which must be disposed after use--a disposable diaper is not something which "can be disposed or kept".

