What is "outer quarter"

Yardarm \Yard"arm`\, n.

1. (Naut.) Either half of a square-rigged vessel's yard[6], from the center or mast to the end.

   Note: Ships are said to be yardarm and yardarm when so near as to touch, or interlock yards.

2. (Naut.) The portion of a yard[6] outboard of the slings, often called the outer quarter.

   Note: A yard[6] is considered to have four unequal quarters, two quarters extending from the mast to the slings on each side, and two smaller outer quarters outboard of the slings.