名詞 entasis:

1. a slight convexity in the shaft of a column; compensates for the illusion of concavity that viewers experience when the sides are perfectly straight

en.ta.sis

n.（名詞）
pl. en.ta.ses[-sôz.]
A slight convexity or swelling, as in the shaft of a column, intended to compensate for the illusion of concavity resulting from straight sides.
柱中微凸線：為了抵消因為直邊所造的中間凹陷幻覺，而在梁柱上放置的小隆凸

來源：
Latin
Latin
from Greek [tension]
from Greek [tension]
from enteinein [to stretch tight]
from enteinein [to stretch tight]
en- [intensive pref.] * see en- 2
en- [intensive pref.] *參見 en-2
teinein [to stretch] * see ten-
teinein [to stretch] *參見 ten-