Plain English Meaning
The weather is good enough to fly by looking outside, with enough visibility and distance from clouds to legally fly under visual flight rules.
Full Definition
Weather conditions in which a pilot has sufficient visibility and cloud clearance to fly the airplane by outside visual reference, meeting or exceeding the minimums prescribed for visual flight rules (VFR) operations.
Context Anchor
Seen in multiengine training, engine-failure discussions, and on the airspeed indicator as the red radial line.
Derivation
From '' (relating to sight), '' (relating to weather, from Greek 'meteoron' meaning 'thing up'), and '' (the of the environment). Together: weather conditions good enough to fly by sight.