From Hard Drop - Tetris Wiki
A top out occurs when:
- a tetromino cannot be placed at least partially within the play zone.
- garbage pieces are sent, pushing the top pieces above the spawn zone.
Top outs result in a game over.
 Loss condition
There are several variations of what constitutes a top out:
- Block out: a piece is spawned overlapping at least one block in the playfield
- Lock out: a piece locks when it is entirely out of bounds (that is, in the vanish zone above the ceiling)
- Partial lock out: a piece locks when it is partially out of bounds, even if it would clear a line
- Garbage out: After lines are cleared and garbage is added, a block remains out of bounds, or an existing block in the field is pushed to 41st or higher row by garbage lines sent to the player
Different games have used different combinations of these conditions:
- This list is incomplete.
- Tetris (NES, Nintendo): a piece locks overlapping at least one block, but in some cases it is possible to move or rotate out of such a situation
- Tetris (Game Boy): a piece locks on its starting position (regardless of rotation) twice in a row. Similar to NES Tetris, it is possible to move the piece out from existing blocks.
- Dr. Mario, Tetris and Dr. Mario, Puyo Puyo, Super Puzzle Fighter II Turbo, Kirby's Star Stacker: block out
- Dr. Mario 64 (Marathon mode): block out or garbage out. The latter condition is checked only when a new virus line is added to the field.
- Columns: block out or garbage out
- Lumines: lock out; the game tries to move the piece one space downleft or downright before ending the game
- Bombliss: garbage out
- Tetris (Atari), Tetris (NES, Tengen), The New Tetris, and Tetris DS (push mode): partial lock out or garbage out
- Tetris Attack: garbage out; in multiplayer mode, evaluation is delayed by a split second
- Tetris DS (standard mode and mission mode) and most other recent games: block out or lock out
- Tetris Best family and Tetris: block out
- Tetris Brick: partial lock out (piece overlaps ceiling on spawn)
- Hatetris: partial lock out