Meanings

duplication

square function

half-duplex transmission

gifted with two things (usu. beauty and intelligence)

derivative work (usu. unauthorized and produced by fans, e.g. dōjinshi, fanfiction)

totally (different)

eighteen

God doesn't give with both hands

what happens twice will happen thrice

dihybrid

binomial equation

behaving in a way characteristic of teenagers going through puberty, esp. by being overly self-conscious

diacidic base

polarisation

second-grade alcohol

first system to rank officials into 12 levels (603 CE)

conjugated double bond

second string (of a shamisen, etc.)

carbon sink

motorcycle, greater than or equal to 250cc