Limit refers to the fact that all bets are of a fixed size, and that there is a limit to how many raises can occur in a round of betting.
In the preflop betting round, there can be a bet, a raise, and a re-raise. In later rounds, there can be a bet, a raise, a re-raise, and a second re-raise.
There is a single round of betting in Kuhn poker. Each player first antes a single chip and is dealt a card from a deck containing one jack, queen, king and ace. The first player then has the option to check, or bet an additional chip. When facing a bet, a player can call the bet or fold. That is, only a single bet is allowed by any player. At showdown, the highest card wins the entire pot. The ace is the highest card.