δι-
di-
“two, twice”
5 words in English grow from this root.
Diapsid
Natureδι-di-
“two arches”
Diarchy
Politicsδι-di-
“rule of two”
Dicotyledon
Natureδι-di-
“two seed cups”
Dimetrodon
Natureδι-di-
“two-measure tooth”
Photodiode
Scienceφῶςphôs
“light two-way”