What is the correct phrase for "shortened words"?

What I'm referring to is sometimes called slang, but I wanted to know if there is an actual name for these kinds of words.

For example, some words might be

• Admin (Administration)
• Fridge (Refrigerator)
• Uni (University)

I was thinking they were abbreviations, but the wiki article on abbreviations seems to say otherwise

An abbreviation (from Latin brevis, meaning short) is a shortened form of a word or phrase. It consists of a group of letters taken from the word or phrase. For example, the word abbreviation can itself be represented by the abbreviation abbr., abbrv. or abbrev.

Solution 1:

One of several words, or a phrase, might suit your purposes. Omitting 'contraction' (see another answer):

stump word: a word formed by abbreviating a single longer one, esp. by reducing it to a single syllable (freq. the first) or the minimum necessary for understanding.

clipping: The shortening of a word, etc.; also, the resulting shortened form.

syncopation or syncope: Contraction of a word by omission of one or more syllables or letters in the middle; transf., a word so contracted.

shrivel (noun) Something shrivelled up ... a contracted word.

The list above omits the obsolete and rare words 'decurtation', 'accurtation' and 'paresis'.

(All definitions from OED Online.)

Solution 2:

You call it "contraction" as it means:

The process of shortening a word by combination or elision.

Example sentences:

‘The contraction of a phrase, word, or part of a word, has the analogy of a telescope being closed: biodegradable for biologically degradable; sitcom for situation comedy.’

‘Yes, since time immemorial, either/or have been as close as two words can get without contraction.’

[Oxford Online Dictionary]