The name of the letter chaf (kaf when there is a dot in its center) is derived from the word kafuf, meaning bent, and alludes to the shape of the letter (which to most English readers looks like a backwards C). It is interesting to note that the palm of one’s hand is also known as a kaf. Whereas the letter yud represented the complete yad (hand, including the fingers), the kaf, palm of the hand, is that which forms a cup and is able to contain things.
When used as a prefix, the letter chaf represents the comparative proposition “like.” Genesis 1:26 reads: “Va’yomer Eh-lohim, na’aseh adam b’tzal'maynu kid’moo'tainu...” And the Lord said ‘Let us make Adam in our image, like our form.”
The letter chaf is also the first letter that has a sofit, a different shape when appearing at the end of a word, with the letter appearing as a right angle with the vertical line hanging lower than the other letters. When used as a suffix, the chaf sofit represents the second person possessive, as in shelach/shelcha, meaning yours (m/f).
Numerically, chaf represents the number 20.
Bibliographical acknowledgment: The Wisdom In The Hebrew Alphabet: The Sacred Letters as a Guide to Jewish Deed and Thought. By Rabbi Michael L. Munk, Mesorah Publications, 1983.