Column
Space
ラン
てすり
柱 （チュウ、はしら） Pillar
棟 （トウ） Pillar
欄 （ラン、てすり） Column, Space
欄 means Column. Space is listed because of Blank Space 空欄, i.e. empty 空 column 欄
Think of the radicals as being a tree 木 and an interval 間 with another tree 木 overlayed on top. The interval 間 between two trees 木 forms a Column 欄