Guild Wars 2

Seen this mentioned on the forums, idk what it is though.

The field is an area the skill creates that other players can use their skills in to create combo attacks.

For instance, the elementalist can lay down a circle of fire that rangers can shoot their arrows through to create fire arrows, or the ranger has a water combo field heal skill that guardians can use a certain hammer skill in to create massive waves in that field that crit heal

to add on what safari said, each skill have in its skill description “Combo field: XXX” or “combo Finisher: XXX” if it can be used as part of a combo

I’ve just started trying to learn more about these, now that I’m joining up with others more in game – I found the wiki pages quite helpful.

http://wiki.guildwars2.com/wiki/Combo

I play a ranger, and mainly solo, so discovered combo fields very early on when first using trap skills. When traps were triggered, I could use the field effect to add additional condition damage on my arrows or melee weapons.

Also, rangers can have a torch equipped with a skill that lays down a fire field for this purpose.

Taking advantage of other professions AoE fields in group attacks is very useful when dealing with champion bosses and the like.