noun

 

proof something which shows that something is happening

Flowers are the first sign of Spring.

 

notice a symbol or message in a public place which gives information or instructions

a road sign

 

symbol a symbol which has a particular meaning

a dollar/pound sign

 

movement a movement you make to give someone information or tell them what to do

 

verb

 

to write your name on something to show that you wrote/painted, etc it or to show that you agree to it

He signs his letters 'Prof. James D. Nelson'.