1. Mail that includes letters and postcards and packages sealed against inspection
   - first class, 1st class, first-class mail

Type of: mail

• incumbent on
• incumbrance
• incunabulum
• incur
• incurability
• incurable
• incurableness
• incurably
• incuriosity
• incurious
• incuriously
• incurrence
• incurrent
• incurring
• incursion
• incursive
• incurvate
• incurvation
• incurvature
• incurve
• incurved
• incus
• incuse
• IND
• indaba