Over/Around Ear or Over Ear often referred to as "full size" headphones - are fairly large and will fit around the entire ear on most headphone users. Properly called circum-aural, meaning "around the ear," full size over ear headphones are what people traditionally picture when headphones are mentioned.
Difference Between On-Ear & Around-Ear Headphones
On-ear headphones’ ear pads rest on the outer ear (upper & lower ear lobe); over-the-ear models' have larger ear pads that encircle the ears. It is a difference in the ergonomic design in the same headphone with headband form factor. On-ear headphones occupy less space & creates a snug fit on the ear. Over-the-ear headphones sound more spacious and expansive than on-ear headphones being wider & bigger in size covering the ear entirely inside the ear cushion.