sigmoid adjective & noun. ['sɪgmɔɪd] L17.
[Greek sigmoeidēs, formed as SIGMA + -OID.]
A. adjective.
1. Chiefly Anatomy. Having the shape of the uncial sigma C; crescent-shaped, semicircular. L17.
sigmoid cavity, sigmoid notch, sigmoid valve, etc.

2. Having a double curve like the letter S; Math. designating or described by a curve or graph having a steep central portion which flattens out at top and bottom. L18.
sigmoid colon, sigmoid flexure Anatomy the terminal portion of the descending colon, leading to the rectum.
b. noun.
1. Anatomy. The sigmoid colon. L19.

2. A sigmoid curve. L19.

■ sigmoi'dectomy noun (an instance of) surgical removal of the sigmoid flexure E20.

■ sigmoi'dicity noun the extent to which a curve is sigmoid (S-shaped) M20.

[TahlilGaran] English Dictionary ▲