Keywords, semantic fields, cohesion & coherence and more!

1- Key word: 

a word that is a key:  a word exemplifying the meaning or value of a letter or symbol

:  a significant word from a title or document used especially as an index to content

2- Semantic field: 

a semantic field denotes a segment of reality symbolized by a set of related words. The words in a semantic field share a common semantic property

3- Cohesion:

a grammatical and lexical linking within a text or sentence that holds a text together and gives it meaning. It is related to the broader concept of coherence.

There are two main types of cohesion: grammatical cohesion which is based on structural content, and lexical cohesion which is based on lexical content and background knowledge. A cohesive text is created in many different ways. In Cohesion in English, M.A.K. Halliday and Ruqaiya Hasan identify five general categories of cohesive devices that create coherence in texts: reference, ellipsis, substitution, lexical cohesion and conjunction.

4- Coherence:

what makes a text semantically meaningful. It is especially dealt with in text linguistics. Coherence is achieved through syntactical features such as the use of deictic, anaphoric and cataphoric elements or a logical tense structure, as well as presuppositions and implications connected to general world knowledge. The purely linguistic elements that make a text coherent are subsumed under the term cohesion.

5- Cognates:

words that have a common etymological origin. In etymology, the cognate category excludes doublets and loan words. The word cognate derives from the Latin noun cognatus, which means "blood relative".

6- False cognates:

pairs of words that seem to be cognates because of similar sounds and meaning, but actually have different etymologies; they can be within the same language or from different languages. That is different from false friends, which may in fact be related but have different meanings.

Even though false cognates lack a common root, there may still be an indirect connection between them (for example by phono-semantic matching or folk etymology).

7- Loan word:

a word adopted from one language (the donor language) and incorporated into a different, recipient language without translation.

1- Source: Merriam-Webster's Learner's Dictionary

2- Brinton, Laurel J. (2000). The structure of modern English: a linguistic introduction. Illustrated edition. John Benjamins Publishing Company.

3- Halliday, M.A.K; and Ruqayia Hasan (1976): Cohesion in English. London: Longman.

4- De Beaugrande, Robert /Dressler, Wolfgang: Introduction to Text Linguistics. New York, 1996. 

5- Crystal, David, ed. (2011). "cognate". A Dictionary of Linguistics and Phonetics (6th ed.). Blackwell Publishing.

6- Crystal, David, ed. (2011). "false cognate". A Dictionary of Linguistics and Phonetics (6th ed.). Blackwell Publishing

7- Grzega, Joachim (2003): “Borrowing as a Word-Finding Process in Cognitive Historical Onomasiology”, Onomasiology Online