Definition of blind
In No-Limit Texas Hold'em, the most popular poker variant and in many other poker variants, there are two types of blinds, the small blind (small blind) and the big blind (big blind). The blind is a forced bet before the start of each hand. On a 10-player table, for example, the small and big blind will move clockwise to all hands. The blinds (small and big) are the two positions to the left of the button (dealer or croupier). So, if in one hand player 1 is button, player 2 will be small blind and player 3 big blind. In the next hand, player 2 will be button while player 3 will be small blind and player 4 will be big blind.
Clarification on the term " blind".
When we talk about "the blinds", we will generally talk about the small blind and the big blind (the players in the blinds). When we talk about a blind, we will generally hear the size of the big blind. On a table where the limit is 5/10 (small blind 5 and big blind 10), if I raise 3 blinds, I don't raise to 15 (3x the small blind), but 30 (3x the big blind).