> a lambda is an "anonymous function," or one that doesn't have a name. I'd frame this slightly differently. The process of defining a function involves: 1. C

> a lambda is an "anonymous function," or one that doesn't have a name. I'd frame this slightly differently. The process of defining a function involves: 1. Creating a function object. 2. (Optional) Assigning a name to it. Lambda is Step 1, and it happens even in programming languages that don't have a so-called "lambda" feature. Such languages always automatically do both steps. Those that do have "lambda" simply make it available to the programmer explicitly, and programmers who use it usually omit Step 2. In Scheme and occasionally in Common Lisp it's not unusual to perform both steps explicitly and use lambda to create named functions. It's fairly common in modern Javascript too. The thing that's new in Excel (since 2020) is the ability to create new functions at all and it's reasonable to just call that "lambda."