Epsilon ∊

Monadic Epsilon means

If ⎕ML=0 Type Of

      ∊ 3 3⍴1 'abc' 
   0         0
        0
   0         0

If ⎕ML≥1 Enlist

      mat
1 2 3
4 5 6
      ∊ 0 mat (7 8) 9
0 1 2 3 4 5 6 7 8 9

      ∊ 2 3⍴1 'abc'
1 abc 1 abc 1 abc

Dyadic Epsilon means Member Of

      'abc' 4 ∊ 4 'ab' 'abcd'
0 1
      mat ∊ 6 2 7 4
0 1 0
1 0 1

Language Elements