aanpäätteeseen

I’m not finding a standard linguistic term "aanpäätteeseen" in Finnish grammar or widely used references. Could you provide more context or confirm what you mean by this term? For example, is it:

- a coined or classroom term describing a particular suffix pattern (perhaps involving the endings -aan and -päätteeseen as illustrating suffixation),

- a reference to a specific Finnish grammar resource or dialect,

- or something else entirely?

If you’d like, I can also write a concise, neutral wiki-style article framing "aanpäätteeseen" as a hypothetical pedagogical term and explain its assumed use in illustrating Finnish suffixation.