onlinePronunciation: /ɒnˈlʌɪn/Translate online | into German Definition of online adjective controlled by or connected to a computer. (of an activity or service) available on or performed using the Internet or other computer network:online banking adverb 1while connected to a computer or under computer control. by means of the Internet or other computer network: shoppers would rather pick up the phone than do business online with processing of computer data carried out simultaneously with its production. 2in or into operation or existence:the new power plant will go online this monthonline in other Oxford dictionaries Definition of online in the US English dictionary