Dictionary.net

• The angle, esp. the least angle, at which a gliding machine or aeroplane will glide to earth by virtue of gravity without applied power.

2010 - New Age Dictionary Database
By Oddity Software

• The angle, esp. the least angle, at which a gliding machine or aeroplane will glide to earth by virtue of gravity without applied power.

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