The Dilemma: You wouldn’t know an Ionic entablature if it bit you on your portico.

People You Can Impress: snooty neighbors with big columns on their porches

The Quick Trick: The more syllables, the more ornate: Dor-ic, I-on-ic, Cor-in-thi-an.

The Explanation:
Although invented by the ancient Greeks, these three architectural orders are still very much alive thanks to the popular Greek Revival styles of government buildings, churches, and museums.

To begin with, the three names refer to orders, or overall styles, but their most recognizable distinctions are in their columns. The simplest and earliest style is the Doric (seventh to fifth centuries bce). Doric columns have no base, the shafts are usually fluted (or grooved), and they’re topped with simple, flared capitals. On top of that lies a square slab known as the abacus. The columns also support the entablature (containing the frieze), which in turn supports the triangular pediment (or basically, the roof). All that’s to say that these features are all pretty plain in the Doric order, and any ornamentation is generally simple and understated. For a (mostly) Doric example, check out the Parthenon.

Next in chronology and complexity comes the Ionic order, arising in the sixth century bce in Greek Ionia. You can’t miss Ionic columns: They have scrolls (or, to be fancy, volutes) at the top and simple bases at the bottom. The tablature is more decorative, including bas-relief carvings of historical events or myths on the frieze. Next time you’re at the Acropolis, note the Erechtheum (it’s not what it sounds like). It’s as Ionic as they come.

That brings us to Corinthian (fourth century bce and later), an order used more in classical revivals than it ever was in classical architecture. Corinthian is the fanciest of the three, and there’s only one word you need to know: leaves. Intricately carved, the leaves and rosettes of Corinthian capitals are said to have been developed by the architect Callimachus and were inspired by an acanthus plant he saw growing through a woven basket on a grave. The base is multilayered, the abacus is concave on each side, and the entablature is divided into many more highly ornamented layers. To see the height of Corinthian-ness, go to D.C. The U.S. Capitol building has more Corinthian columns than it knows what to do with.

Extra Credit
Italian Renaissance architects recognized two additional orders: the Tuscan, a style even plainer than Doric, with unfluted columns and unadorned entablatures, common in Georgian architecture; and the Composite, a ridiculously ornamented style that combined Corinthian leaves, Ionic volutes, and anything else you wanted to throw in there.