bound stems

[GoodTaste]

Is "bound" an adjective here? Why not just write "stems"?

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The suffix -al that changes nouns and bound stems to adjectives has two other forms, -ial and -ual. For now let's analyze some adjectives that contain them, in order to get used to seeing and hearing them.

Source: ck-12 https://www.ck12.org/spelling/The-Suffixes-al-ial-and-ual/lesson/Suffixes-al-ial-and-ual/

 

[jutfrank]

You've asked two questions.

1) Yes, it is.
2) Because that wouldn't say that the stems are bound.

I'm not sure where your second question comes from. Are you asking what bound stems are?