Yes, although I would use Mail Merge to change them in all of the documents instead.

You could bookmark the words in the source document and use an IncludeText field:
{ INCLUDETEXT "deleteme.docx" "test" \* charformat }


{ INCLUDETEXT "filename" "bookmarkname" \* charformat }

If you do not have the "\* charformat" switch you get source formatting.
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You can use the Insert > QuickParts > Fields method to insert the field.
00 deleteme 1.png

Once you have it down, typing the field is quicker. Remember that the field-delimiter braces must be inserted in pairs using Ctrl+F9.

Thank you very much for your reply. As a start I see that it is quite easy to use the "includetext" function, but I might look into Mail Merge.

Best regards