Orthogonally directed
For an orthogonal direction , we say a polyomino is "-directed" if every cell of the polyomino can be reached from an anchor cell without going opposite that direction.
For example, the following polyomino is up-directed with the bottom-left cell as an anchor, since every cell in it can be reached from that cell without going down:
Note that the anchor cell is not necessarily unique, as any cell on the bottom row can be used as an anchor cell.