The Collaborative International Dictionary of English v.0.48:

In \In\, n.

   Note: [Usually in the plural.]
   1. One who is in office; -- the opposite of out.
      [1913 Webster]

   2. A re["e]ntrant 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]