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

Type of: mail

• expeditiousness
• expel
• expellee
• expeller
• expelling
• expend
• expendable
• expender
• expending
• expenditure
• expense
• expense account
• expense record
• expensive
• expensively
• expensiveness
• experience
• experienced
• experient
• experiential
• experiment
• experimental
• experimental condition
• experimental extinction
• experimental method