- An angle formed by the perpendicular intersection of two straight lines; an angle of 90°.直角，90度角：由两条直线垂直相交而成的角；90°角
- indecomposable
- indecorous
- indecorum
- indeed
- indef.
- indefatigable
- indefeasible
- indefectible
- indefensible
- indefinable
- indefinables
- indefinite
- indefinite article
- indefinite integral
- indefinite number
- indefinite pronoun
- indehiscent
- indelible
- indelicacy
- indelicate
- indemnification
- indemnifications
- indemnified
- indemnifies
- indemnify