Middle names and their meanings

[litherland lass]

I am researching my nan's family tree. She was one of 6children. Her mother's maiden surname was either McVitie or Vetere( the data on screen was not clear,so had to guess which one) but no mention of the names highlighted below.
3 of her siblings have middle names that seem to be more of a surname.
Of these 3, two of them have the same middle name. Neither of their parents had middle names.
The first sibling is Mary ACTON Baines and then there is Thomas ACTON Baines, with the third child Harold KNOWLES Baines. They where all born in the Everton area of Liverpool from1884 to 1894. Other siblings have what I would call ordinary middle names of Norman, Agnes, with the sixth no middle name.
The ACTON name has been given to both male and female. This seems to be a possible previous family name? So could the same be said for KNOWLES?
Any suggestions

[Milliepede]

I think you will have to go back to see what the parents mothers maiden names were.  Or maybe even further back to see if those names appear.   

James Baines married Mary McVitie 1883 her mother was -

Mary Joyson/Joynson married John McVitie 1847 her parents were -

James and Elizabeth but haven't found her maiden name yet. 

[litherland lass]

Thank you Milliepede.
That's great.
I had only gone back to my nan's father and mother's date of birth using the BDM site and therefore extracted their data which only gives you quarters. This new info allows me now to do more research. However, my main aim was to work forwards on my mum and dad's siblings which is hard going but interesting.
If you look at the Caernarvon site you will find my entries re my grandfather Evan Roberts.
Thanks again
Litherland Lass.