It depends on the implementation of course, but clearing 4 lines at once usually brings a huge amount of points. For example, NES version at the first "level" (slowest speed):

1 line = 40, 2 lines = 100, 3 lines = 300, 4 lines = 1200.

It also increases the speed every 10 lines, so you want to plan accordingly for maximum score. You can get above that first level with either 400 points or 3600.

If you have some time to kill, highly recommend this and the follow up video: https://www.youtube.com/watch?v=9RaqVGzhQTM

In modern ("guideline") tetris T-spins multiline clears tend to actually be the most point-garnering moves. It's a bit weird that the game named tetris went that way but oh well.

"Tetris" as in "tetrahedron". mind.equals(blown).

More like tetris as in Tetromino: https://en.m.wikipedia.org/wiki/Tetromino

"Tetra" isn't completely unknown in English but perhaps the link is more obvious to Russian-speakers (the original author was Russian)? Is четыре/chetyre a cognate of Greek-derived tetra?

https://translate.google.com/?sl=en&tl=ru&text=four