Term: Offense
Explanation: Offensive teams rely on outspeeding and outdamaging the opponent directly. Players using this style of play will often utilize hard-hitting Pokemon and use resistances and immunities to switch into attacks as opposed to defined walls to take hits. Tactics include: lures to eliminate counters, using stat boosters, and utilizing a quick Stealth Rock in order to facilitate kills. The suicide lead is an expansion of the quick Stealth Rock concept and is often used by offensive teams. A suicide lead is essentially a Pokemon in the lead position whose role is to stop the opponent from setting up Stealth Rock and at the same time set up its own Stealth Rock, such as Aerodactyl and Azelf.
Example: Sand Offense teams
Reference: The Pokemon Dictionary
Term: Balance
Explanation: This type of team does not rely on any single type of Pokemon. Generally speaking, balanced teams have a couple of sweepers, backed up by a number of walls and/or tanks. Most teams of this type will utilize a form or two of entry hazards. The most successful balanced teams often revolve around a certain threat, while the other teammates seek to help guarantee a sweep by the said threat.
Example: CB Tyranitar supports RP Landorus-I to sweep a team, with Ferrothorn setting up hazards and Unaware Clefable as a Cleric
Reference: The Pokemon Dictionary
Term: Stall
Explanation: Stall teams are based off of residual damage. This damage can come in many forms, including: sandstorm, hail, Toxic Spikes, Spikes, and Stealth Rock. The majority of Pokemon on a team like this will have good defenses and contribute to the overall goal of indirectly fainting the opponent's team. Tactics include using Ghosts to block Rapid Spin (a move which can eliminate entry hazards), setting up entry hazards as fast as possible, and using Pseudo-Hazing (Phazing) moves, such as Perish Song, Whirlwind, and Roar.
Example: Standard Stall team: Mega Sableye, Jirachi, Tentacruel, Hippowdon, Chesnaught, Heatran
Reference: The Pokemon Dictionary
this is fun :]
Term: Pivot (Defensive / Offensive)
Explanation: A pivot is a Pokemon that is generally only used for switching. Due to good defensive stats and a solid defensive typing, they can usually take little damage as they switch in, and the opposing switch they force allows the player to switch again safely to another Pokemon. An offensive pivot will force a switch by threatening KO on the opponent, thus obtaining momentum, whereas a defensive pivot will be difficult to break past, and thus will slow the opponent's momentum.
Example: Mega Ampharos (Defensive), Scarf Landorus-T (Offensive)
Reference: The Pokemon Dictionary
Term: Supporter
Explanation: A Pokemon who uses non-offensive moves which benefit the team.
Example: Ferrothorn, Heatran
Reference: The Pokemon Dictionary