In other languages usually the world "coercion" is used for implicit conversion, i.e. int->long, int->float, float->complex. str->unicode in Python 2 (that's what PyUnicode_FromObject() does). But the last conversion is not supported in Python 3. The term "coercion" has also been used in Python 2 in the narrow sense (see the __coerce__() method), and in this sense Python 3 does not support "coercion". Therefore, I believe that it is better to avoid the use of this term.