These names are not interchangeable: tables, balls, markings and scoring logic vary. Knowing the differences prevents incompatible purchases and makes practice more focused.
Pool
Pool uses six-pocket tables, generally smaller balls and compact table formats. Eight-ball and nine-ball have different objectives and shot order, so confirm the rules and ball set before buying.
Pyramid
Russian pyramid uses large balls and tight pockets. Free, combined and dynamic versions change which balls and shots are permitted and how points are counted.
Snooker and carom
Snooker uses six pockets, fifteen reds and colours, with safety and break-building at its core. Carom has no pockets: a point comes from contacting both object balls under the discipline's rules.
Start with one discipline, read its current rule set and practise on a compatible table.