Chelsea defines five commonly used words by hikers. 

Out & Back

Out & Back is a type of trail that starts and ends at the same location.

Scree

Scree are in formations, normally large ones of small rocks normally at the bottom of a mountainside. 

Pee Cloth

Pee Cloth is a piece of material that you can use to wipe after peeing trail and it's great for keeping in line with Leave No Trace Principles.

Trekking Poles

Trekking Poles are, normally metal, long sticks that you can use on trail to support yourself. 

Ultralight

Ultralight is normally said with gear. Ultralight gear is a lighter option that you can buy for your gear.