Does AWS CloudSearch have default stems and synonyms?

Question

In the CloudSearch admin console, I see that you can add your own stems and synonyms. Does this override an internal default list of stems and synonyms or is there no such default list and you are required to add stems and synonyms before CloudSearch uses these features?

Answer 1

Regarding stems:

Stems are specified as a collection of term and stem pairs. When you configure stemming options, the existing stemming dictionary is replaced with the mappings you specify. By default, Amazon CloudSearch does not define any stems. However, some basic algorithmic stemming is always performed, such as removing plural suffixes. (This is done whether or not you specify a custom stemming dictionary.)

Regarding synonyms:

By default, Amazon CloudSearch does not define any synonyms.

To complete the answer, regarding stop-words:

By default, Amazon CloudSearch defines the following stopwords for English (en):

a
an
and
are
as
at
be
but
by
for
in
is
it
of
on
or
the
to
was