I do not like overture, but the little tool that listed the number of searches for a particular term for the prior month was great to find out the search terms that were not too competitive, but allowed me to sneak into the top three results for $0.05 or $0.06 cents. The problem is that there is no such thing for Google.
Is the closest thing in google the number of results?
is there an actual tool or some other way to figure it out?
Try Wordtracker (dont know if i can post the link here so i will just say "wordtracker dot com" LOL) this will give you a good idea of search terms (not for Google specifically). Don't know if adwords at google still gives you an estimate of keyword impressions or not.
Google has their Adwords Suggestions tool at https://adwords.google.com/select/main?cmd=KeywordSandbox, although it does not give impression counts. What is useful though is the Similar Keywords Suggestions that is like a lateral approach and helps you expand your mindset.