<p>There’s the general definition and the U.S. News ranking definition.</p>
<p>Generally speaking, liberal arts college (LAC) around here and most places is used colloquially to refer to small (typically < 5,000), undergraduate-only or mostly undergraduate colleges. LACs are typically characterized by their small class sizes - which often permit close relationships with professors and more discussion in classes. Generally speaking, they also pride themselves on the “liberal arts education,” which is a well-rounded general education that requires students to take classes in the social, natural, and physical sciences as well as the humanities and mathematics/quantitative reasoning. They tend not to have professional majors, although that may vary and some LACs are actually professionally focused - like Babson College, which is an LAC focused on business. Smith also has an engineering major, and Harvey Mudd is focused on the sciences and engineering. Examples of the more traditional kinds of LAC are Amherst, Swarthmore, Rhodes, Reed, Occidental, Sweet Briar (women’s), Wesleyan (women’s), Spelman and Morehouse (historically black).</p>
<p>U.S. News defines a liberal arts college for the purpose of their ranking as a college that “emphasizes undergraduate education and awards at least half of their degrees in the liberal arts fields of study.”</p>
<p>The “liberal arts” part is the least relevant part of the definition, because you can study the liberal arts at large national universities and most large national universities consider themselves liberal arts institutions. For example, at Columbia - a large research university - you’ll take courses in the Core Curriculum designed to make you a well-rounded individual, and most of their majors are not pre-professional (there’s no business major, or communications, for example).</p>
<p>The biggest differences between LACs and universities are</p>
<p>-Size - generally speaking. LACs tend to have less than 5,000 undergrads and I would say that most probably have less than around 3,000 undergrads. But they’re not the only ones. Rice, for example, has only ~3,000 undergrads itself, despite being a research university. Tufts is also pretty small, with just over 5,000 undergrads. The size tends to mean smaller classes and classes that are more like seminars than lectures.</p>
<p>-Major research programs and graduate programs. At large national universities like Columbia, Harvard, Penn State or UCLA, the professor’s primary job is as researcher. Professors are expected to bring in major grants and publish a lot of papers. They need lots of graduate students to do that, especially in the sciences. This often (but not always) means for undergrads that they will have grad students doing some part of the teaching in their major. This also differs by department. Grad students may teach your science labs and math labs, or they may teach entire classes. For example, at Columbia advanced graduate students can apply to teach the Literature Humanities and Contemporary Civilization classes in the Core, and most sections of University Writing are taught by English graduate students (and I actually think it’s required as part of the PhD program in English). The math and science tutoring rooms and the writing center are also usually staffed by a mix of grad and undergrad students, supervised by a faculty member. It may or may not be more difficult to get close to professors, depending on your personality and the size of the school.</p>
<p>LACs don’t have major research programs and usually have no or very few graduate programs, so the professor’s primary job is typically to teach (although at elite colleges, they share that responsibility with doing research - they usually only teach 4 classes a year, about equivalent to what a professor at an Ivy would teach, whereas at mid-ranked colleges they may teach 5 or 6). Therefore, your labs probably will be led by the professor, and you likely won’t have any classes taught by a grad student.</p>