Kith and kin
What's the meaning of the phrase 'kith and kin'?
One's kith and kin are one's friends and relations.
What's the origin of the phrase 'kith and kin'?
Many of us use 'kith and kin' to refer to our family, imagining that the use of two words is for emphasis, as in phrases like aid and abet, chop and change etc. 'Kin' is well known to mean family and has been used as such in English since at least the 9th century. 'Kith' however is a less familiar word, in fact we don't really use it anymore except in this phrase. Kith doesn't mean family, it means 'the things well known', like one's surroundings, one's country. This also is a very old English word and has been used, initially to mean 'the things one is acquainted with', since around 900AD. 'Uncouth', in its original meaning, was the opposite of kith, that is, 'the things not understood or accepted'.
The earliest used of 'kith and kin' in print is found in William Langland's Middle English narrative poem The vision of William concerning Piers Plowman, 1377:
Fer fro kitth and fro kynne yuel yclothed ȝeden.
[Far from kith and from kin they evil-clothed went.]
For a usage in modern English with our currently used spelling we have to wait until the late 18th century, when Robert Burns used it in the text of his Poems & Songs: circa 1796:
My Lady's white, my Lady's red, And kith and kin o' Cassillis' blude.