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.
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)
'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".
It doesn't fit all of your examples, but throwaway?
It means "denoting or relating to products that are intended to be discarded after being used once or a few times".
ephemeral: 'lasting for a very short time.'
Shockingly, the word mono-use is (literally) unfindable in Google.
In Italian it's monouso, do I need to explain its meaning? Isn't it self-explanatory? You use it one time
But someone has caught on and given the name mono-use in their patent for a hypodermic syringe
The invention relates to syringes suited for hypodermic injections and more particularly to mono-use syringes for hypodermic injections.
The use of mono-use "throw-away" syringes is known. Typically, "throw-away" syringes are packaged singularly in hermetically sealed wrappers. This simple type of packaging is practical and guarantees sterility of the syringe up until the moment that the syringe is used.
A problem associated with "throw-away" syringes is the possibility of reuse of the syringe for further injections. Because there is no assurance of hygienic conditions, repeated use of "throw-away" syringes increases risk of transmission of various types of diseases. The problems associated with the repeated use of "throw-away" syringes has been well documented in the case of intravenous drug abusers who commonly use syringes previously used by others.
The use of mono-use syringes having various mechanisms to render the syringe inoperable after a single use is also known.
You could extend the use of mono and tag it onto almost anything e.g. "mono-user account" for those who wish to open a temporary account which would expire after a limited period. And "mono-use link" could be shortened to mono-link which is easier to pronounce than "single-use link". It could catch on.