Weak typing usually implies a system where types get coerced easily:
php -r "echo '4' + 4;"
ruby -e "'4' + 4"
-e:1:in `+': no implicit conversion of Fixnum into String (TypeError)
from -e:1:in `<main>'
I deliberately used "weak" in the title as a loose umbrella term for the sundry malpractices detailed below. The article is hopefully otherwise quite specific.
In particular, by "types", I always mean "static types" or "propositions". What you mean mean by "dynamic types", I call "tags"; they are not the topic of the article. These usages are standard, if not universally adhered to; I hope I made this clear in the article.