Difference between variation and line in chess

I have zero knowledge about these concepts. What does variation and line mean? While creating a study when I right click a move there are options like promote variation, force variation, make mainline. What does these things actually mean? Can anybody please help me understand these things?

A line is a set of chess moves that follows one after the other, creating a game. A mainline is one of the most common chess lines played out. A variation is a mainline that took off in another direction at some point along the route. The different types of variations like force, promote, etc, are stating how the variation starts.

Variations and lines are almost the same thing. For instance, Sicilian Defense: Closed Variation is an opening variation, of which many lines can develop. A line is often comprised of more moves than a variation as you will talk about this line of play or that line of play developing from a specific opening variation.

@Behilit
@ahamz
Thanks, now I understand what variation and lines are. But still I dont understand what promote variation and force variation are.

Promote variation means you want to turn a variation into a mainline or a sub-variation into a variation (or a sub-sub-variation into a sub-variation etc.)

Example:

1. e4 c6 2. d4 d5 3. Nc3 (3. e5 Bf5) dxe4 - There are two lines here, a mainline and a variation. The mainline is 1. e4 c6 2. d4 d5 3. Nc3 dxe4, the variation is 1. e4 c6 2. d4 d5 3. e5 Bf5. If you promoted the variation it would become 1. e4 c6 2. d4 d5 3. e5 (3. Nc3 dxe4) Bf5.

Not sure what "Force Variation" means.

No big difference.

basically side line = variation.

@Bookmarked "Force Variation" means to create a variation when there's no mainline, or alternatively, make something at the end of the game a variation.

@HighlyRadioactive thank you very much