When you type in pinyin, it's easy to pick the wrong homophone.
Tips
culture
Homophones shape many customs. Fish, 鱼, is served at New Year because it sounds like 余 (surplus), and nobody gives a clock as a present, 送钟, because it sounds like 送终 (to attend a dying parent).
usage
For whole words that sound alike, the term is 同音词.