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

Paradigmatic relations exist between units of the language system outside the strings where they co-occur. They are based on the criteria of selection and distribution of linguistic elements. Paradigmatic relations determining the vocabulary system are based on the interdependence of words within the vocabulary: synonymy, antonymy, hyponymy, meronymy.
F. de Saussure called paradigmatic relationships associative relationships, because they represent the relationship between individual elements in specific environment.
It was the Danish linguist Louis Hjelmslev who replaced the term associative relations for paradigmatic relations.
Syntagmatic relations are immediate linear links between the units in a segmental sequence. Syntagmatic relations are horizontal since they are based on the linear character of speech.
In psycholinguistics these terms are used in a different sense.
The term paradigmatic relations denotes the mental associations between words which form part of a set of mutually exclusive items, e.g. black responds with white.
The term syntagmatic relations refers to mental associations between words which frequently occur together, e.g. black magic / tie / sheep.
30. Synonyms. the notion of a synonymic dominant. Types of synonyms. Sources of synonymy.
Synonyms (Gr. syn ‘with’, ónyma ‘name’) are two or more words belonging to the same part of speech and possessing a common denotative semantic component, interchangeable at least in some contexts without any considerable alteration in sense, but differing in morphemic composition, phonemic shape, shades of meaning, connotations, style, valency and idiomatic use, e.g.:
The synonymic dominant is the general term of its kind potentially containing the specific features rendered by all the other members of the group. It is characterised by:
high frequency value;
broad combinability;
broad general meaning;
lack of connotations;
stylistic neutrality;
it may substitute for other synonyms at least in some contexts;
it is often used to define other synonyms in dictionary definitions