in \in\, n.

   note: usually in the plural.
   1. one who is in office; -- the opposite of out.
      1913 webster

   2. a re"entrant angle; a nook or corner.
      1913 webster

   ins and outs,
      a nooks and corners; twists and turns.
      b the peculiarities or technicalities of a subject;
          intricacies; details; -- used with of; as, he knew the
          ins and outs of the washington power scene.
          1913 webster +pjc

                all the ins and outs of this neighborhood. --d.
                                                  jerrold.
          1913 webster
see also:
out ins and outs 

22 moby thesaurus words for "ins and outs":
   chain of circumstances, chain reaction, chapter of accidents,
   circumstances, concatenation of events, context, details,
   environment, existing conditions, feast and famine,
   full particulars, minutiae, particulars, ropes, set of conditions,
   status quo, total situation, ups and downs, vicious circle,
   vicissitudes, vicissitudes of fortune, whole picture