レイ, したが.う, しもべ
slave, servant, prisoner, criminal, follower
JLPT1 G7 S16 F2009
隸 is the left-hand element# as described in 款 (carve characters) + 隶 seize. (Distinguish 隶 from the identical-appearing lower element of 康; also, compare 逮.) 隸 thus means to seize captives and tattoo them → *slave*; *servant* → *follower*. For the connection between tattoos and slaves, compare 妾. Although 隸 is the form consistent with the term's etymology, 隷 has become standard in Japanese usage.
[Full Kanji Etymology List]