n. one of four children born at the same time from the same pregnancy
n. a muscle of the thigh that extends the leg
n. (printing) a block of type without a raised letter; used for spacing between words or sentences
n. 四倍( quad的复数形式 ); 空铅; （大学的）四周有建筑物围绕的方院; 四胞胎之一