ac‧ro‧nym / ˈækrənɪm / noun [ countable ]
a word made up from the first letters of the name of something such as an organization. For example, NATO is an acronym for the North Atlantic Treaty Organization.
ab‧bre‧vi‧a‧tion / əˌbriːviˈeɪʃ ə n / noun
1 [ countable ] a short form of a word or expression
abbreviation of/for
‘Dr’ is the written abbreviation of ‘Doctor’.
Register
In everyday English, people usually say be short for instead of be the abbreviation of/for :
W.H.O. is short for ‘World Health Organization’.
2 [ uncountable ] the act of abbreviating something