ne'o VUhU3 cmavo

unary mathematical operator: factorial; a!.

On affix form:

x1 is a/the neck [body-part] of x2; [metaphor: a relatively narrow point].

In notes:

x1 is the factorial of x2.
ma'oi'e (exp!)
Like "ma'oi" but outputs the officially-designated/canonical sub-selma'o (if any) to which the immediately following and quoted word (cmavo) belongs, otherwise outputting the whole relevant selma'o in fashion equivalent to "ma'oi".