Well, I know what a ligand, chelate or chelation is, but I have never wondered how I can describe it to someone who does not know any chemistry. So, I tried to find out the roots and the first use of these terms.
According to wikipedia and many other websites, articles and books, the term "chelate" was first used in chemistry in 1920 by Gilbert Morgan and D.K. Drew. I took the quote from the wikipedia page: (A paper I am reading right now says that the word "ligand" was first used by Stock in 1917. But, it says the description of "chelating" was introduced by Drew and Morgan.)
"The adjective chelate, derived from the great claw or chele (Greek) of the lobster or other crustaceans, is suggested for the caliperlike groups which function as two associating units and fasten to the central atom so as to produce heterocyclic rings."
And below is the article. Unfortunately, it is behind a paywall.
Obviously, I had to look for what "chele" (chela) looks like:
I also found some useful definitions for some terms here in the same article above although I've never heard some of them: