Dictionary.net

• A straight line considered as drawn from a center to an indefinite distance in one direction, the complete ray being the whole line drawn to an indefinite distance in both directions.

2010 - New Age Dictionary Database
By Oddity Software

• A straight line considered as drawn from a center to an indefinite distance in one direction, the complete ray being the whole line drawn to an indefinite distance in both directions.

1913 - Webster's Revised Unabridged Dictionary
By Noah Webster.