Heterographs are words that sound the same but have different spelling and meaning. E.g. To, Too, Two.
Homophones are words that sound the same but have different meanings. (note could have similar spelling). E.g. Gases or Gasses.
Take a look at this for a complete explanation. Especially the chart:
http://en.wikipedia.org/wiki/Homophones
Two different words that have the same meaning are called synonyms.
CONTRANYM
Have the same meaning or not, it is a rhyming word.
The formation or use of words such as buzz or murmur that imitate the sounds associated with the objects or actions they refer to is called onomatopoeia.
Words that have the same or almost the same meaning are called synonyms. Synonyms can often be used interchangeably in sentences, although they may carry slightly different connotations or be appropriate in different contexts. Examples include "happy" and "joyful" or "fast" and "quick." Understanding synonyms can enhance vocabulary and improve communication.
A homonym for "fall" is "faul," which sounds the same but has a different meaning.
A homophone.
homophone
Two different words that have the same meaning are called synonyms.
Homophones are words that sound the same but have different meanings and often different spellings, such as "buy" and "by."
They are homographs.
ryming words
onomotopeia
It is literacy device " Pun". that means use of word that sounds alike but have different meaning of create humor.
Hiss and hoot both refer to sounds made by animals. A snake or a cat makes a hiss (a sibilant sound that has an sss sound). People can also be said to make an angry sound called a hiss. An owl makes a hoot (which sounds like "hoo, hoo"); monkeys also have a call that is called a hoot. People can be said to hoot with laughter. So hiss and hoot both describe animal or human sounds, but they are very different sounds and different in meaning.
An imitator
Words that are spelled the same but have different pronunciations and meanings are called homographs.