abbreviation と acronym と initialism はどう違いますか？説明が難しい場合は、例文を教えて下さい。

Often, abbreviations, acronyms and initialisms are all called "abbreviations". And initialisms are almost always called "acronyms". But there are differences between these three words.

Initialism
An initialism uses the first letter of each word (or of each important word). These letters are not pronounced like a word. They are said separately.
RSPCA (pronounced "R-S-P-C-A") = Royal Society for the Prevention of Cruelty to Animals
NHS (pronounced "N-H-S") = National Health Service
WO (pronounced "WHO") = World Health Organization

Acronym
NATO (pronounced /ˈneɪtəʊ/ ("naytoh")) = North Atlantic Treaty Organisation

Abbreviations use some of the letters of a word (or of words).
e.g. (from Latin ‘exempli gratia’) means "for example"
i.e. (from Latin ‘id est’) means that is, or in other words
Dr is a common abbreviation for "doctor". It uses the first letter and the last letter. But it isn't pronounce "d-r" and it isn't pronounced "drrr". The full word "doctor" is always spoken.
Another common abbreviation is oz for "ounce" or "ounces". The abbreviation is the same for singular and plural. I don't know where the 'z' comes from. It just is "oz".

This web page talks about abbreviations and gives several examples.
https://dictionary.cambridge.org/grammar/britis...