Terror bombing is a technique of strategic bombing. By late war it chiefly involved area bombing of residential neighborhoods of heavily populated urban areas using a mix of high explosive fragmentary bomb and incendiary munitions in the purposeful attempt to cause massive firestorms as a way of more effectively destroying structures (and the people inside them) then purely HE fragmentary bomb raids. This categorized RAF doctrine since 1941-42 and USAAF since late 1944 into 1945, especially into the Pacific, where limitations on daylight precision bombing forced the same situation to justify nighttime area terror bombing with incendiary munitions with various justifications about going after cottage industry, workers homes, etc, where the real justification, according to countless quotes of the men in charge, was to terrorize the enemy into surrendering by targeting their morale. Its no different then the nuclear theory of countervalue strikes against population centers holding no military value to force an enemy surrender or better yet prevent war through deterrence of massive casualties, the only difference being (as MacCurdy demonstrates in his book on morale) that atomic bombs work at breaking morale, while conventional bombing, even with incendiaries, does not.The use of the term 'terror bombing' indicates a lack of objectivity. An interesting appraisal of the Dresden bombing can be found here: The WWII Bombing of Dresden: Propaganda and Mythology. By: Michael W. Kramer
I already stated that the Feb 45 Dresden raid (the one the OP is asking about) was operational level bombing, it wasn't designed to get the Germans to surrender, not designed to do anything more than cause mass damage to impede movement of troops and logistics, cause traffic buildup, cause a major regional emergency requiring aid to be delivered to the city, all while in conjunction with a massive Soviet offensive aimed at crossing into the eastern German border. In that, I actually think it would have been worthwhile if it had been conducted about 2-3 weeks earlier, while the Soviets were still launching their offensive in the area, which by the time the raid was actually conducted, was already over with, making the raid kind of superfluous.