doorbell – n. a device which visitors can ring to announce their arrival

vision – n. the state of being able to see

surveillance – n. close observation

digital – adj. related to the use of computer technology

match – v. to make equal in quality or strength;

discount – n. a price reduction

analyst – n. someone who works as an observer

burglary – n. stealing; robbery

data – n. facts and other information collected together for study

opportunity – n. a chance or possibility
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