Bachelorette, the word which is highly searched on internet, originated from bachelor. Bachelorette is more popular among American English speaking people, and also used by magazines and journalists for unmarried or single woman.
Bachelorette got famous when it was used for dating game show on TV, especially for female contestants who are supposed to find their soul partner through such dating game shows.
Bachelorette used to be used for spinster but now in modern English or in internet era it is commonly used for female contestants. But when it was used in old English, it was considered for the woman who never got married and had any children.
In different countries, there are different meanings for Bachelorette. In Canada, it refers to a small apartment but still it has a separate bathroom, living room and a bedroom.