Final answer:
Entasis is an architectural technique where columns slightly swell in the middle to counteract the illusion of tapering due to human visual perception, adding dynamism and an organic feel to the structure. These subtle adjustments are a hallmark of Greek design.
Step-by-step explanation:
The term entasis refers to the intentional architectural design technique used by the Greeks, particularly noticeable in their column designs. This technique involves making slight adjustments, such as a subtle swelling in the middle of a column, to account for visual perception. Without these adjustments, columns could appear to taper inappropriately due to the tricks played by human vision. Beth suggests that these deviations contribute to giving buildings a sense of dynamism and a more organic feel. Columns are not perfectly straight but include a slight convex curve to express the weight of the structure above, as described by Steven, who notes that Greek columns feature a bulge, demonstrating the entasis, about a third of the way up from the base.