To wit is now just a fixed expression. It’s a shortened form of that is to wit meaning “that is to know; that is to say; namely”, from the English verb wit “to know”. This was a strong verb with past tense wot, as in “A garden is a lovesome thing, God wot”. In Old English it was spelt witan, and even further back it was linked with a Germanic verb meaning “to see”. In the first of these senses, it’s closely connected with the modern German verb wissen; in the second it’s the origin of our witness. It developed further to refer to a person’s understanding or judgement or mind (hence “keep your wits about you”).
"Wit" is also the source (from wissen) of "wisdom" or the "rule of vision (or of understanding, metaphorically).
Frank
Posted by: Frank Glenn | June 15, 2008 at 07:04 PM