Someone recently asked me what I thought of using the word addendum in connection with contracts. I’m not crazy about it.

Black’s Law Dictionary defines addendum as “Something to be added, esp. to a document; a supplement.” So an addendum adds something to a contract, but it’s not clear whether you’re amending or supplementing the contract. (MSCD 17.10 discusses the distinction between amending and supplementing.)

Furthermore, addendum is a Latinism, and it isn’t one of those Latinisms that’s so ingrained that they can now be accepted as English.

So I suggest that you use instead amendment or supplement, whichever applies.

About the author

Ken Adams is the leading authority on how to say clearly whatever you want to say in a contract. He’s author of A Manual of Style for Contract Drafting, and he offers online and in-person training around the world. He’s also chief content officer of LegalSifter, Inc., a company that combines artificial intelligence and expertise to assist with review of contracts.