cipher

a message written in a secret code

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

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"

a person of no influence

a secret method of writing

convert ordinary language into code; "We should encode the message for security reasons"

make a mathematical calculation or computation