The words steal, steel, stele sound the same but have different meanings and spellings. Why do steal, steel, stele sound the same even though they are completely different words?
The answer is simple: steal, steel, stele are homophones of the English language.
To take (the property of another) without right or permission.
To present or use (someone else's words or ideas) as one's own.
To get or take secretly or artfully: steal a look at a diary; steal the puck from an opponent.
To give or enjoy (a kiss) that is unexpected or unnoticed.
A generally hard, strong, durable, malleable alloy of iron and carbon, usually containing between 0.2 and 1.5 percent carbon, often with other constituents such as manganese, chromium, nickel, molybdenum, copper, tungsten, cobalt, or silicon, depending on the desired alloy properties, and widely used as a structural material.
Something, such as a sword, that is made of steel.
A quality suggestive of this alloy, especially a hard, unflinching character.
Steel gray.
An upright stone or slab with an inscribed or sculptured surface, used as a monument or as a commemorative tablet in the face of a building.
The central core of tissue in the stem or root of a vascular plant, consisting of the xylem and phloem together with supporting tissues.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.
If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally "different writing").