The words crew, krewe sound the same but have different meanings and spellings. Why do crew, krewe sound the same even though they are completely different words?
The answer is simple: crew, krewe are homophones of the English language.
A group of people working together; a gang: a crew of stagehands.
A group of people gathered together temporarily; a crowd.
All personnel operating or serving aboard a ship.
All of a ship's personnel except the officers.
New Orleans Any of several groups with hereditary membership whose members organize and participate as costumed paraders in the annual Mardi Gras carnival: "They . . . watched a parade of bands and New Orleans-style floats run by krewes throwing necklaces of colored beads” ( Robert Reinhold). See Regional Note at beignet.
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.