To ask for urgently or peremptorily: demand an investigation into the murder; demanding that he leave immediately; demanded to speak to the manager. To claim as just or due: demand repayment of a loan. To ask to be informed of: I demand a reason for this interruption. To require as useful, just, proper, or necessary; call for: a gem that demands a fine setting. Law To summon to court. Law To claim formally; lay legal claim to. To make a demand. The act of demanding. Something demanded: granted the employees' demands. An urgent requirement or need: the heavy demands of her job; the emotional demands of his marriage; an increased oxygen demand. The state of being sought after: in great demand as a speaker. Economics The desire to possess a commodity or make use of a service, combined with the ability to purchase it. Economics The amount of a commodity or service that people are ready to buy for a given price: Supply should rise to meet demand. Computer Science A coding technique in which a command to read or write is initiated as the need for a new block of data occurs, thus eliminating the need to store data. Law A formal claim. Archaic An emphatic question or inquiry. on demand When presented for payment: a note payable on demand. on demand When needed or asked for: fed the baby on demand.