Difference between "Search Volume" & "Average Monthly Searches"

Hi Friends!

I use keyword planner for keyword research. I encounter with 2 words in the search matrix.
I generally use average monthly searches for deciding the keywords still I want to know what does this "Search Volume" signifies.

Please give me insight - "Search Volume" Vs "Average Monthly Searches"

Thank you.

from Google AdWords http://bit.ly/2J6wRzZ
via IFTTT