A lottery syndicate is a group of people that split the cost of a lottery ticket and all its potential winnings.
This makes playing the lottery cheaper and increases your chances of winning, though the winnings will be smaller.
For instance, say one lottery ticket costs $10.
A lottery syndicate of 300 people might buy 10 lottery tickets per day.
Over the course of the month, this adds up to 300 lottery tickets for $10 per person.
This gives every individual in the syndicate 300 chances to win for only $10.
On the other hand, if one of the syndicate's ticket happens to win $15,000,000, each member of the syndicate will only receive $50,000.
Most of the best online lottery sites offer a predefined or a custom lottery syndicate option.