|The following definition appears in the BR script and the
Marvel Comics adaptation of the film, and the Denver/Dallas sneak
_android_ (an'droid) n, Gk. humanoid automation. more at robot./
1. early version utilized for work too boring, dangerous or
unpleasant for humans.
2. second generation bio-engineered. Electronic relay units and
positronic brains. Used in space to explore inhospitable environments.
3. third generation synthogenetic. REPLICANT, constructed of
skin/flesh culture. Selected enogenic transfer conversion. Capable
of self perpetuating thought. Para physical abilities. Developed
for emigration program.
WEBSTER'S DICTIONARY New International (2012)
Replicants are manufactured organisms designed to carry
out work too boring, dangerous, or distasteful for humans.
The "NEXUS 6" replicants are nearly indistinguishable from
humans. (In one draft of the script Bryant tells Deckard they did an
autopsy on the replicant that was fried trying to break into the Tyrell
Corp. and didn't even know it was a replicant until two hours into the
Replicants presumably differ from humans in one
important factor: they are lacking in empathy.
In BR, the replicants' eyes glow (even those of an
artificial owl), however Ridley Scott has stressed that this is merely a
cinematic technique, and the glow can't be seen by the characters in the
story, only by the audience.
The manufacturers noticed that replicants had
eccentricities because they were emotionally immature. Rachael was a
prototype replicant with experimental memory implants, designed to
provide a cushion for her emotions.
Consequently, she was unaware that she was a replicant.
NEXUS 6 replicants have an in-built fail-safe mechanism,
namely a four year lifespan.