Yes, lead is playable
...and is worth 6 points.
Found in the following dictionaries
Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)
"Lead" Definition
noun
A channel of open water created by a break in a mass of ice.
A lead weight suspended by a line, used to make soundings.
A soft, malleable, ductile, bluish-white, dense metallic element, extracted chiefly from galena and used in containers and pipes for corrosives, solder and type metal, bullets, radiation shielding, paints, and antiknock compounds. Atomic number 82; atomic weight 207.2; melting point 327.5°C; boiling point 1,744°C; specific gravity 11.35; valence 2, 4. See Table at element.
A thin stick of such material.
adjective
First or foremost: the lead leg on a surfboard.
Most important: the lead author of a research paper.
Acting or serving as a lead or .
idiom
Get the lead out Informal To start moving or move more rapidly.
Lead the way To be foremost in an endeavor or trend: The firm led the way in the application of new technology.
Lead the way To show a course or route by going in advance.
Lead up to To proceed toward (a main topic) with preliminary remarks.
Lead up to To result in by a series of steps: events leading up to the coup.
phrasal-verb
Lead off Baseball To be the first batter in an inning.
Lead off To begin; start.
Lead on To keep in a state of expectation or hope; entice.
Lead on To mislead; deceive.
verb-transitive
Printing To provide space between (lines of type) with leads.
Sports To pass a ball or puck ahead of (a moving teammate) so that the player can receive the pass without changing direction or losing momentum.
To aim in front of (a moving target).
To be a channel or conduit for (water or electricity, for example).
To be ahead of: led the runner-up by three strides.