Smith's Bible Dictionary
Oak. (Hebrew, strong). There is much difficulty in determining the exact meanings of the several varieties of the term mentioned above. Sometimes, evidently, the terebinth or elm is intended and, at others, the oak. There are a number of varieties of oak in Palestine.
(Dr. Robinson contends that the oak is generally intended, and that it is a very common tree in the East. Oaks grow to a large size, reach an old age and are every way worthy the venerable associations connected with the tree. - Editor). Two oaks, Quercus pseudo-coccifera and Quercus aegilops, are well worthy of the name of mighty trees; though it is equally true that over a greater part of the country, the oaks of Palestine are at present merely bushes.
These files are public domain.
Smith, William, Dr. Entry for 'Oak'. Smith's Bible Dictionary. https://www.studylight.org/dictionaries/eng/sbd/o/oak.html. 1901.