e·co·sys·tem 
(ēkō-sĭs′təm, ĕkō-)
(ēkō-sĭs′təm, ĕkō-)n.
An ecological community together with its environment, functioning as a unit.
- free skater
- free skating
- free sledding
- free soil
- free-soil
- Free-Soiler
- free speech
- free spirit
- free-spoken
- freest
- freestanding
- Free State
- Free State
- freestone
- freestyle
- freestyler
- free-swimmer
- free-swimming
- free-swinging
- freethinker
- freethinking
- free thought
- free throw
- free throw lane
- free-throw line