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
- Top out: 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 left-down or right-down 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