the hockey puck is made round like a ball because it wouldn't be able to move if it was like a ice hockey puck because in ice hockey it can glide in filed hockey you need to be able to roll it around easyily
On the ice, a hockey puck is pushing against much less surface friction, so it will slide with relative ease. On the street, a puck is forced to push against the pavement which it cannot do very well causing it to either stop or bounce across the surface.
An offside in ice hockey is when a player from the attacking team has crossed over the defending teams blueline before the puck. It is a delayed offside when nobody from the attacking team touches the puck.
Interference in ice hockey is when you hinder the movement of a player who does not possess the puck. You can body check the play with the puck and no penalty will be called. If you body check a player away from the puck, an interference penalty will be called.
The first hockey pucks were made out of rubber or wood, but were square, not round. The first indoor ice hockey game at Montreal's Victoria Skating Rink (later home to the Canadiens) in 1873 used a round wooden puck.