dialectical relates to the tension between opposites. Pick "anything", there's something else in conflict with it, causing it to be, or not to be. This contrasts with a frictionless immutable analysis, where there's no interaction between the "anything" you're analysing and it's surrounding context.
historical means that this analysis is applied to historical aspects of society.
materialism means that any support on the analysis must be originate in material reality, with as much context as possible. In contrast with idealism, which is kind of moral judgement on what things look like, or should be.

Am I too far off?