What is the meaning of [2,1-c][1,4] in Pyrrolo[2,1-c][1,4]benzodiazepine?
Yes, the order of the numbers indicates the relative orientation of the fused ring system. The direction of the numbers of the attached component (e.g. ‘1,2’ or ‘2,1’) corresponds to the direction of the lettering of the parent component (i.e. a, b, c, etc.).

For example:





The correspondig Subsection P-25.3.1.3 in the current version of Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book), reads as follows:


  (…)
  Isomers are distinguished by lettering, continuously, each peripheral side of the parent component (…) using the italic letters a, b, c, etc., beginning with a for the side numbered ‘1,2’, b for ‘2,3’ etc. To the letter as early in the alphabet as possible that denotes the side where the fusion occurs are prefixed, if necessary, the numbers of the positions of attachment of the other component. These numbers are chosen to be as low as is consistent with the numbering of the compound and their order conforms to the direction of lettering of the parent component. (…)