Testing validity of a word

[uzibalqa]

I want to test whether a word is valid. Is there a package in Emacs for 
dictionary word lookup ?

Have constructed something like this, but of course the function lookup-word 
does not exist.

(defun is-valid-word (word)
  "Check if the WORD is valid using the Emacs dictionary."
  (let ((dict-info (lookup-word word)))
    (if (plist-get dict-info :found)
        t ; The word is valid.
      nil))) ; The word is not valid.

Is there a package in Emacs for dictionary word lookup ?