'long-sent' is a compound word formed from 'long' and 'sent', where 'long' means 'extended in duration' and 'sent' is the past participle of 'send', meaning 'to cause to go or be taken to a particular destination'.

'Long-sent' combines the Old English 'lang' (meaning 'long') and the Middle English 'sent', derived from the Latin 'sentire', meaning 'to feel or perceive'.

Initially, it referred to messages that were 'sent over a long distance', but now it generally refers to messages that are 'extended in length'.