Lexical cohesion is the cohesive effect achieved by the selection of vocabulary.
Lexical cohesion is basically created by the general nouns, or repetition
of the same lexeme, or the use of other lexical relations as cohesive patterns.
Lexical cohesion refers to the ties created between lexical elements,
such as words.
For example, mechanics, or groups of words.
Quantum mechanics and phrases to carry out research.
These lexical ties can occur over long passages of text or discourse.
The primary paradigmatic types of cohesion, meaning words of the same type
of class, are repetition, synonymy hyponymy and meronymy.
Repetition means using the same word over again, but
not restricting to the same morphological form.
In this short example the author repeats the word motion four times.
Synonymy: using words that are in the same way synonymous, or,
in the case of autonomy, in some way autonomous.
The word study and research, they are synonyms.