monosemy - is the property of having only one meaning
metonymy - a figure of speech in which the name of one object is substituted for something closely associated with it
- e.g. “The White House declared that we are at war with Mars”
- “The White House” is a metonymy for “The President”

Term	Description	Examples	Meaning	Spelling	Sound
Homonym	same spelling or pronunciation but different meaning		DIFF	ONE OR MORE SAME
Homograph	same spelling but different meaning		DIFF	SAME	EITHER
Homophone	same pronunciation but different meaning or spelling		ONE OR MORE DIFF		SAME
Heteronym	same spelling but different pronunciation and meaning	desert (noun) desert (verb)	DIFF	SAME	DIFF
Heterograph	same pronunciation but different spelling and meaning	to two	DIFF	DIFF	SAME
Heterophone	same spelling but different pronunciation and meaning	desert (noun) desert (verb)	DIFF	SAME	DIFF
Synonym	same meaning	couch sofa	SAME	EITHER	EITHER
Polyseme Polysemy	same spelling but related and distinct meanings	mouth (face) mouth (river)	DIFF But Related	SAME	EITHER
Capitonym	same spelling but different meanings when upper case	Polish (noun) polish (verb)	DIFF When Capitalized	SAME Except for Capitalization	EITHER

Polyseme vs Homonym

Both polysemy and homonymy words have the same syntax or spelling. The main difference between them is that in:

polysemy, the meanings of the words are related
homonymy, the meanings of the words are not related

For example, if we talk about the same word “bank”:

polysemy: ‘a financial institution’ and ‘the building in which such an institution is located’ # similar meanings
homonym: ‘a financial institution’ and ‘a river bank’ # different meanings

Terms - Other

sound	spelling	meaning	examples
✘	✘	✘	NA
✘	✘	✔	couch - sofa
✘	✔	✘	desert (noun) - desert (verb)
✘	✔	✔	address - address
✔	✘	✘	to - two
✔	✘	✔	color - colour
✔	✔	✘	fall (verb) - fall (noun)
✔	✔	✔	any word with itself