guard(In a statechart or activity diagram, a condition that specifies when an event can take place. Whenever its event fires, a guard is evaluated only once)
shelter Cover or protection, as from weather or danger; place of refuge; conservation No definition needed; shielding device Barriers devised for keeping away from people harmful substances; defence The act or process of protecting citizens or any geographical area by preparing for or by using military means to resist the attack of an enemy; refuge A restricted and isolated area in which plants and animals persisted during a period of continental climatic change that made surrounding areas uninhabitable; especially an ice-free or unglaciated area within or close to a continental ice sheet or upland ice cap, where hardy biotas eked out an existence during a glacial phase. It later served as a center of dispersal for the repopulation of surrounding areas after climatic readjustment; conservation; shelter; shielding device
