subject line noun [C]

the words in the space at the top of an email that describe what the email is about:

Please put your reference number in the subject line.

• purchase
• purchase agreement
• purchase invoice
• purchase ledger
• purchase order
• purchase price
• purchaser
• purchase requisition
• purchasing
• purchasing officer
• purchasing power
• purchasing power parity
• pure monopoly
• pure play
• pure profit
• purse
• pursuant
• pursue
• purveyor
• push
• push strategy
• push system
• put
• put option
• PV