The phrase "mighty oak" refers to a big, strong, and powerful oak tree. It represents something or someone that is strong, resilient, and enduring. Full definition
Hard, crunchy leaves from the nearby mighty oak tree hit the west - facing windows with loud! (soupaddict.com)
Sonoma County is home to ancient redwood forests, stands of mighty oak, and scenic, rugged coastlines. (sonomafamilylife.com)
“ Mighty oaks from little acorns grow» certainly applies to Honda, which last year accounted for almost ten percent of new - vehicle sales in the United States. (automobilemag.com)