Terminologies

Tetris, especially modern, has a lot of Terms, so here's is a small page on what everything means in context:

Term	Explanation
7 Bag	All 7 pieces will appear in a random order BUT every piece will appear before the next bag gets used Ex.: ljtoizs, szloitj, jsloitz, every piece once, in a random order
L J O I T S Z	The name of the pieces
Line, Row	Line is horizontal, Row is vertical
Well	The unfilled section of your stack that you clear lines in
Harddrop HD, Softdrop SD	SD is when you Accelerate the falling of a piece but don't place it down instantly, HD: Instant placement
CW CCW	Clockwise, Counterclockwise rotation
Single/Double/Triple/Quad/Tetris	A clear of 1/2/3 or 4 Lines
Kick	A kick is a rotation of a piece and how it interacts with the Rotation system
SRS	Super rotation System: the most common Rotation system that most games use (other include SRS+, ARS, BiRS,...)
Spin	A spin is when you position a piece but in order to get it in you cant just drop it (such as T-spin)
TSS/TSD/TST	T spin Single, Double or Triple
Stack	How the player has built their board
Garbage	When you clear lines, you send garbage to the opponent
Messy/Clean	The cleaner the board is means how little chaos is on the board: Smooth top, 1 Well only, the stack doesn't cover holes, the more the opposite is true, the messier the board is, and if the garbage lines you get from your opponent are unclean, thats called cheese
CT4:	Count to 4, as in Count to 4 lines for a Tetris
6-3, 7-2, 9-0 etc.	This Term is for the width of stacks on the board e.g.: 6-3 means you have 6 rows of blocks, 1 free one and then 3 filled rows
1/2/3/4w	1/2/3/4wide, Wide means the length of the well, so 4w means a 4 wide well to clear lines in
Opener	A Strategy where, because of the 7 Bag system, you can build a set-up at the start of the game with ease and speed, such as TKI or PCO