If a person reaches age 62 in 2015, for example, then 2015 is the person's year of eligibility. We always index an individual's earnings to the average wage level two years prior to the year of first eligibility.
rill - a small channel (as one formed by soil erosion) channel - a deep and relatively narrow body of water (as in a river or a harbor or a strait linking two larger bodies) that allows the best passage for vessels; the ship went aground in the channel.
A quill is a pen made from a flight feather of a large bird, most often a goose. Quills were used as instruments for writing with ink before the metal dip pen, the fountain pen, and eventually the ballpoint pen came into use. Quill pens were used in medieval times to write on parchment or paper.