S Your new gas furnace may have been installed in one of two. ways, as a direct-vent (2-pipe-Fig. 2) application or as a. non-direct vent (1-pipe-Fig. 3) application. S In a direct-vent (2-pipe) application,your furnace uses air. from outside the home for combustion and ventsflue gas to the. outdoors.
For the biological concept, see Anti-predator adaptation. A defence mechanism is an unconscious psychological mechanism that reduces anxiety arising from unacceptable or potentially harmful stimuli. Sigmund Freud was one of the first proponents of this construct.
Meaning: A structure used to defend against attack. Classified under: Nouns denoting man-made objects. Synonyms: defensive structure; defense; defence. Context example: the artillery battered down the defenses. Hypernyms (defence is a kind of...): construction; structure (a thing constructed; a complex entity constructed of many parts)