The term 'put in the mail' is a phrase used to describe the process of sending a letter or package through the postal service. The crossword solutions for this term are POST (4 letters), SENT (4 letters), SEND (4 letters), and POSTED (6 letters). POST is an abbreviation of the verb 'to POST', which means to SEND something through the mail. SENT is the past tense of the verb 'to SEND', which also means to SEND something through the mail. SEND is the present tense of the verb 'to SEND'. Finally, POSTED is the past participle of the verb 'to POST'.