semiotics

n [sing v] study of signs and symbols, esp in writing, and of what they mean and how they are used 符号学（研究符号和符号使用行为的学科）.

semaphore, semblance, semen, semester, semi, semi-, semi-conscious, semi-detached, semi-skilled, semibreve, semicircle, semicircular, semicolon, semiconductor, semifinal, semifinalist, seminal, seminar, seminarist, seminary, semiprecious, semiquaver, Semite, Semitic, semitone, semitropical, semivowel, semolina, sempstress, SEN, senate, senator, senatorial, send, send away for, send for, send for sb., send in, send off, send out,