de ri·gueur 
(də rē-gœr)
(də rē-gœr)adj.
Required by the current fashion or custom; socially obligatory.
[French : de, of + rigueur, rigor, strictness.]
- interne
- interne
- internecine
- internee
- internet
- internetwork
- interneuron
- interneuronal
- internist
- internment
- internodal
- internode
- inter nos
- internship
- internuclear
- internuncial
- internuncially
- internuncio
- interoceptive
- interoceptor
- interoffice
- interoperability
- interoperable
- interpeduncular
- interpenetrate