Yes, there is
yes, there is a way. I forgot how I accomplished this on my MBP before upgrading to a newer model and found this thread. I'll post the steps when I can.
You need to edit the CSS file located here:
`/Library/Dictionaries/Oxford Dictionary of English.dictionary/Contents/DefaultStyle.css`
Open in a text editor and, depending on your last update/version of os, head down to line 970. Look for this selector:
`html.apple_client-panel body`
It should have a default value of 14px (lower value of px means smaller font and vice versa). You will need to restart after you save (browser).