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

Partial homonyms are words found within different (rarely the same) parts of speech which coincide only in some of their forms, i.e. their paradigms are not identical. e.g.:
seal, n. (seals) ‘a semi-aquatic marine mammal’ – seal, v. (sealed, sealing) ‘to close tightly’; lie, v. (lies – lying – lay – lain) ‘to be in a horizontal or resting position’ – lie, v. (lies – lying – lied – lied) ‘to make an untrue statement’;
According to the type of meaning, homonyms are classified into:
lexical homonyms, if they belong to the same part of speech but differ in lexical meaning, e.g.:
bank, n. ‘land along the side of a river’ – bank, n. ‘an establishment for keeping money, valuables, etc.’;
lexical-grammatical homonyms, if they belong to different parts of speech and differ both in their lexical and grammatical meanings, e.g.:
bear, n. – bear, v.; right, adj. – write, v.;
grammatical homonyms, i.e. homonymous word-forms of one and the same word differing in grammatical meaning, e.g. the homonymy of the plural, Possessive Case singular and plural: bears - bear's - bears'.
29. Syntagmatic vs paradigmatic relations among English words.
Paradigmatic and syntagmatic relations are understood as basic linguistic relationships describing the complex structure of a language system. This distinction is relevant to all levels of description. It was introduced by the Swiss linguist Ferdinard de Saussure in 1916 as a generalisation of the traditional concepts of a paradigm and a syntagm.
Paradigm (Gr. parádeigma ‘pattern, model’) is a set of homogeneous forms opposed to each other according to their semantic and formal features.
Syntagm (Gr. sýntagma ‘that which is put together in order’) is a structured syntactic sequence of linguistic elements formed by segmentation which can consist of sounds, words, phrases, clauses, or entire sentences.