This is the traditional definition of trademarks. Smell or scent is among the non-traditional trademarks that are registrable under the laws of some countries like the USA, the UK, Canada, Australia, New Zealand, UAE, Korea, France and Colombia.
In an article entitled “Scent trademark registration” dated Dec. 23, 2022 on The Trademark Lawyer Magazine, Rajiv Suri wrote that for a smell to be registered as a trademark, the usual requirements are: (1) the ability to describe the smell as accurately as possible, (2) its distinctiveness is established through long and continuous use and (3) the product should not be used to sell a specific smell – thus, the scent of perfumes and fragrances cannot be trademarked.
Examples of registered smell trademarks are: (1) a “high impact, fresh, floral fragrance reminiscent of Plumeria blossoms” used in connection with sewing thread and embroidery yarn (in the US), (2) a rose fragrance as applied to vehicle tires (in the UK) and (3) the scent of Play-Doh.