1. Susceptibility to injury or damage: In Greek mythology, Achilles' mother tried to make him impossible to be injured, hurt, or wounded by dipping him into the magical waters of the River Styx; however, the heel by which she held him made this vulnerability the cause of his death when an arrow hit him in his heel during a military battle.

2. The degree to which a population, species, ecosystem, agricultural system, or other biological entity is unable to cope with the adverse effects of climate changes: Throughout the three years of almost total draught, the vulnerability of producing enough vegetables and grains hit the farmers quite hard and bankruptcy was not uncommon.

The characteristics of electromagnetic vulnerabilities consist of a system that can cause it to suffer a definite degradation (incapability of performing a designated mission) as a result of having been subjected to a certain level of electromagnetic environmental effects.

In computer protection, the ability of an invader to violate the integrity of a computer system: Security vulnerabilities may result from weak passwords, software bugs, a computer virus, or other malware, or a script code injection.

A security vulnerability is classified as a serious problem if it is recognized as a possible means of attack.

One dimension of multiple stressors and shocks, including natural hazards: These social vulnerabilities refer to the inability of people, organizations, and societies to withstand adverse impacts from multiple stressors to which they are exposed.

These impacts of social vulnerabilities are caused in part by characteristics inherent in social interactions, institutions, and systems of cultural values.

In antiterrorism, a threat and vulnerability assessment involves the pairing of a facility's threat analysis and vulnerability analysis.

In computer operations, a systematic examination of an information system or product: A vulnerability analysis is used to determine the competence of security measures, recognize security deficits, furnish data from which to predict the efficiency of proposed security measures, and verify the adequacy of such measures after effectuation.

A program that performs the diagnostic phase of an analysis, also known as a computer assessment: A vulnerability scanner analysis defines, identifies, and classifies the security holes (vulnerabilities) in a computer, server, network, or communications infrastructure.

In addition, a vulnerability scanner functions as an analysis which can forecast the effectiveness of proposed countermeasures, and evaluate how well they work after they are put into use.

A time frame within which defensive measures by the armed forces are reduced, compromised, or lacking: The window of vulnerability is used with reference to military defenses of strategic assets, and also by analogy in computer software to a "vulnerability" which is open to exploitation by hackers.