Homonyms

In linguistics, a homonym is one of a group of words that share the same pronunciation but have different meanings, whether spelled the same or not. A more restrictive definition sees homonyms as words that are simultaneously homographs (words that share the same spelling, regardless of their pronunciation) and homophones (words that share the same pronunciation, regardless of their spelling).The relationship between a set of homonyms is called homonymy.

Example :

• Accept (to receive) and Except (excluding)
• Ad (advertisement) and Add (short for addition)
• Affect (to influence) and Effect (result)
• Aid (to assist) and Aide (an assistant)
• Air (stuff we breath) and Heir (one who will inherit)
• Aisle (walkway) and Isle (island)
• Allusion (an indirect reference) and Illusion (a misconception)
• Ant (insect) and Aunt (parent's sister)
• Capital (city) and Capitol (wealth and resources)
• Days (more than one day) and Daze (to bewilder)
• Die (to become dead) and Dye (coloring agent)
• Emigrate from (leave one country) and Immigrate to (enter another country)
• Gorilla (large ape) and Guerrilla (military soldier)
• Knead (working bread dough) and Need (must have)
• Mail (postal delivery) and Male (masculine person)
• Than (a comparison) and then (shows time)
• There (a place) and Their (belongs to them) and They're (they are)
• To (a preposition) and Too (an adverb) and Two (a number)
• Your (possessive pronoun) and You're (you are)

Although included in the above list from Weber State University, several of these words are not technically homonyms. They are spelled the same and have different meanings; but, they don't sound the same if pronounced correctly:

• Accept and except
• Affect and effect
• Than and then
• Elicit and illicit
• Emigrate and immigrate

 References :

https://en.wikipedia.org/wiki/Homonym

http://examples.yourdictionary.com/examples-of-homonyms.html