1 [noncount] a : the state of being protected or safe from harm
▪ We must insure our national security. — often used before another noun ▪ an electronic security system ▪ random security checks ▪ security measures
b : things done to make people or places safe
▪ The college failed to provide adequate security on campus after dark. ▪ increased security at airports ▪ There was a lapse in security and the inmates escaped.
c : the area in a place (such as an airport) where people are checked to make sure they are not carrying weapons or other illegal materials
▪ We have to go through security at the airport.
d : the part of a company or other organization that provides protection for workers, equipment, etc.
▪ We called security when we found the door open. 2 [noncount] : the state of being closely watched or guarded
▪ The meeting was held under tight security. ▪ The prisoner was being kept under maximum security. 3 [noncount] : the state of being free from anxiety or worry : the state of being or feeling secure
▪ financial security ▪ She is concerned about job security. [=about the possibility of losing her job] ▪ I like the security of knowing there will be someone there to help me when I need help. ▪ Growing up in a close family gave her a sense of security. 4 [count] a : something given as proof of a promise to make a payment later
▪ security for a loan
b : a document showing that someone owns or has invested in a company, organization, etc.
▪ government securities