Metal Gear series

Metal Gear Games
The term Metal Gear Series refers to both the original games and to collection of all canonical Metal Gear Games.

The original Metal Gear Series consists of Metal Gear and Metal Gear 2 Solid Snake.

The full canonical Metal Gear Series consists of both Metal Gear and Metal Gear Solid Games.

Metal Gear Series
Metal Gear Metal Gear 2 Solid Snake Metal Gear Solid Metal Gear Solid 2: Sons Of Liberty and its remakes Metal Gear Solid 3: Snake Eater and its remakes Metal Gear Solid 4: Guns of The Patriots and its remakes

Metal Gear Games
The Term Metal Gear Series is not normally used to refer to non-canonical games, they are more often refered to simply as Metal Gear Games.