I don't understand

I don’t understand why the understand rule is not working in my program.

[code]The mound of dirt is a thing in Cemetery.

Understand “dirt” as “mound of dirt.”[/code]

This produces the message:

Problem. You wrote ‘Understand “dirt” as “mound of dirt.”’ : but if ‘understand … as …’ gives the meaning as text then it must describe a single new token, so that ‘Understand “group four/five/six” as “[department]”’ is legal (defining a new token “[department]”, or adding to its definition if it already existed) but ‘Understand “take [thing]” as “drop [thing]”’ is not allowed, and would not make sense, because “drop [thing]” is a combination of two existing tokens - not a single new one.

By default, it already recognizes “dirt” as “mound of dirt”. I dunno if that is what is making it unhappy, but you don’t need that Understand.

edit: Er, but if you do, it should probably be Understand “dirt” as the mound of dirt.

Lux is correct–but also, you don’t need the second set of quotation marks. It should be:

Understand "dirt" as the mound of dirt.

The first one is a quoted string (or something like that), the second one is an object you’ve defined (or sometimes a kind of thing, or some other things.)

Thanks to both.