1. a mathematical element that when added to another number yields the same number

2. a quantity of no importance;

"it looked like nothing I had ever seen before"

"reduced to nil all the work we had done"

"we racked up a pathetic goose egg"

"it was all for naught"

"I didn't hear zilch about it"

3. a person of no influence

4. a secret method of writing

5. a message written in a secret code

1. convert ordinary language into code;

"We should encode the message for security reasons"

2. make a mathematical calculation or computation