The five definitions of science

The word “science” is used in many different ways. As a scientist and a consumer of science, I find it helpful to try to identify which definition of the word people mean when they say “science.” Below are the most common definitions I have heard people use:

Definition 1: an unbiased, systematic way to collect and analyze evidence towards answering or understanding a question or phenomenon.

As in, the study of a topic using the scientific method.

Definition 2: the body of knowledge obtained via the scientific method.

I think the popularity of this definition stems from primary education, in which students take science classes, such as high school biology, that do not necessarily teach the scientific method, but rather facts obtained using it.

Definition 3: the study of the natural world using technology.

This is sort of an implicit definition. I think very few people will give this definition when explicitly asked to define science, but many will subscribe to it without realizing. I find this to be the most common definition of science, even among scientists.
By this definition, the social sciences, such as psychology and economics, are not considered science. Although, I have heard the social sciences being referred to as “soft sciences” in contrast to the natural sciences, e.g., physics, chemistry, and biology (the “hard sciences”).
This is my least favorite definition, as I think the underlying belief here is that fields like human psychology and sociology are not real sciences because they study complex, intricate topics without the use of the most advanced technology (e.g., fancy microscopes and particle accelerators). This definition also lends to the dangerous bias that the better the technology used in a study, the better the science.

Definition 4: an antonym for “magic;” as in, the process of providing mechanistic explanations for a phenomenon.

For example, I once heard someone say that a certain food has been scientifically proven to taste better than another, since scientists showed that it contains more umami-receptor binding chemicals. “Scientifically proven,” in this usage, refers to the discovery of the biologic mechanism underlying why something may taste good.
In contrast, per Definition 1, “scientifically proven” would instead mean that a randomized, blinded experiment showed that significantly more people prefer the taste of one food over another. Of course, even then, taste is subjective to each individual and it would be difficult to argue one food is proven to taste better.

Definition 5: an antonym for “art;” as in, a method that relies on precise quantifications.

This definition is exemplified by the phrase “they’ve got this down to a science.” In cooking, for instance, getting the process down to a science would mean measuring out the ingredients exactly, whereas a more “artful” cooking process would involve measuring by eye and taste. Quantification is fundamental to the scientific method, so I kind of like this definition. However, it seems to downplay the importance of creativity in science.