1. a component of production
something that goes into the production of output

2. any stimulating information or event
acts to arouse action

Synonym: stimulationstimulusstimulant

3. a statement that expresses a personal opinion or belief or adds information

e.g. from time to time she contributed a personal comment on his account

Synonym: remarkcomment

4. signal going into an electronic system

Synonym: input signal