What is meant by first name?

There are three parts to a name: 1st , middle and surname.

Your first name is the most important because its what you expect people to call you by. First names are only occassionally named after surnames like Hudson Jones or Smith Wright. Middle names can be first names or surname, for example Georgina Adams Smith or Rebeecca Laura Smith. Surnames can be double barrelled, like Smith-Jones or Arkwright-Smith or can be singular like Smith. It used to be very common for boys' first names or middle names to be named after their father's surname.

For example: Smith Wright was named after his father John Smith