intransitive verb
Definition: To communicate or express something using gestures, symbols, or sign language.
Example: She can sign fluently in American Sign Language.
noun
Definition: A symbol or object that conveys information or instructions, often used to indicate something or to advertise a place.
Example: The traffic sign warned drivers to slow down.
transitive verb
Definition: To write one's name on a document to show approval or agreement, or to use gestures to communicate.
Example: She decided to sign the contract after reviewing all the details.