Branches of linguistics. Synchronic vs diachronic approaches to the language study. Lexicology – ‘the science of the word’ Lexicon

According to the semantic relations between the constituents:

non-idiomatic compounds, whose meanings can be described as the sum of their constituent meanings, e.g. a sleeping-car, an evening-gown, a snowfall;

compounds one of the components of which has undergone semantic derivation, i.e. changed its meaning, e.g. a blackboard, a bluebell;

idiomatic compounds, the meaning of which cannot be deduced from the meanings of the constituents, e.g. a ladybird, a tallboy, horse-marine. The bahuvrihi compounds (Sanskrit ‘much riced’) are idomatic formations in which a person, animal or thing is metonymically named after some striking feature (mainly in their appearance) they possess; their word-building pattern is an adjectival stem + a noun stem, e.g. bigwig, fathead, highbrow, lowbrow, lazy-bones.
Shortening. Types of shortening.

Shortening is the process of substracting phonemes and / or morhemes from words and word-groups without changing their lexico-grammatical meaning.

Abbreviation is a process of shortening the result of which is a word made up of the initial letters or syllables of the components of a word-group or a compound word.