Second nature is a phrase that refers to an acquired skill that has been practiced for so long that it appears to be effortless or innate. It may be used to describe a person for whom unusual things have become routine due to repetition, as in the case of a mother who holds a fussy baby while cooking dinner and folding laundry. The idiom is also often used when talking about a particular talent that was developed over time, for instance a skilled quarterback throwing touchdowns. It can also refer to learning a foreign language. Second nature has also been adopted by a number of consumer products, from baby bottles to pet training devices.
The expression is a shortened form of an ancient proverb, custom becomes second nature, that was first recorded around 1390 AD. It refers to the fact that repeating or practicing an initially difficult task over and over makes it seem more and more natural. It also suggests that the best way to master a new skill is through intense practice and that anything, no matter how unfamiliar at first, can be learned through repetition. Something that has become second nature is also usually done repeatedly over a long period of time, such as a factory worker performing a specific task on an assembly line. Second nature can also be used to describe an ability that may not be obvious, such as a very petite person being able to lift heavy items.
The phrase comes from the Latin secondum naturam, meaning according to nature. The term was first used in Aristotelian philosophy to contrast with phenomena described by the Latin as super naturum (above nature), contra naturum (against nature), or supra naturum (beyond nature). These were generally concepts, including divine miracles, the occult, and others, that were believed to exist outside of the confines of the natural world.
A number of consumer products have also adopted the phrase second nature. It is a brand of baby bottle that claims to be the most similar to breastfeeding, allowing breastfeeding mothers to also use bottles. A number of products related to landscaping and gardening have also adopted the name, possibly to emphasize organic and environmentally friendly practices. It is also the title of a 2003 movie starring Alec Baldwin, in which the main character struggles to remember his forgotten past after waking from a coma.