The Keyword Planner Average Monthly Searches for phrases "meaning of names" and "driving licence" are 301000 and 90500 respectively. So the "meaning of names" has search volume more than three times bigger than "driving licence".
The "Avg. monthly searches" column explanation says: "About the number: We calculate the 12-month average of the number of searches for this exact keyword based on the location and Search Network targeting settings that you've selected (not including your language setting). " (bold mine)
On the other hand, the Google Trends chart shows approximately the same search volume for both phrases within my chosen period, which is the last 12 months.
The explanation of the "Interest over time" column says: "The numbers on the graph reflect how many searches have been done for a particular term, relative to the total number of searches done on Google over time.".
Judging from the explanations, both data shows volume for these particular (exact) search terms. Also, the volume is for the last 12 months in both cases.
So, why is the proportion between these volumes approximately 1:3 in Keyword Planner and 1:1 in Google Trends?