Sing is the more general term, and it can be used to describe any type of vocal music, from opera to pop. Croon, on the other hand, is a more specific term that is used to describe a particular style of singing that is characterized by a soft, gentle voice and a slow tempo.
Another key difference between sing and croon is that sing can be used as both a transitive and intransitive verb, while croon is only used as an intransitive verb. This means that sing can be used to describe both the act of producing musical sounds with the voice and the act of performing a song, while croon can only be used to describe the act of producing musical sounds with the voice.
Finally, sing is a more common word than croon. This is likely due to the fact that sing can be used to describe a wider variety of vocal music.
Here are some examples of how sing and croon can be used in sentences:
* John sings in the choir.
* Maria crooned a lullaby to her baby.
* The band sang a song about love.
* The crooner performed his latest hit song.
As you can see, sing and croon are two different words with different meanings and uses. However, they are both related to the act of producing musical sounds with the voice.