Hydrant ⍎

Monadic Hydrant means Execute expression

      ⍎ '1+1'
2
      V ← 1 2 3
      ⍎ 'V'
1 2 3 

Dyadic Hydrant means Execute expression in given namespace

      '#' ⍎ '⎕PP ⎕CT ⎕RL'
┌──┬─────┬────┐
│10│1E¯14│┌┬─┐│
│  │     │││1││
│  │     │└┴─┘│
└──┴─────┴────┘