sis

As an adverb wis

is certainly, surely.

As an adjective wis

is certain.

As a verb wis

is to know.

As an initialism SIS is

Secret Intelligence Service

As a noun sis is

shortened form of sister.

As a numeral sis

is six.

As a noun psis is

.

As a numeral sis

is six.

As a noun sid is

fairy mound or sid can be peace, goodwill, peaceableness, a state or period of peace, a truce; peace terms; peacemaking, conciliation.

As nouns the difference between sais and sis

is that sais is a groom, or servant with responsibility for the horses while sis is shortened form of sister.

As a verb sais

is form of Nonstandard spelling|says.

As a proper noun Saïs

is a city in ancient Egypt.

As an initialism SIS is

Secret Intelligence Service

As a numeral sis

is six.

As a noun sips is

.

As a noun sies

is .

As a numeral sis is

six.

As a noun sirs

is .

As a numeral sis is

six.

As a numeral sis

is six.

As a noun sig is

a special interest group; a group formed to discuss a particular topic or issue.

As a numeral sis

is six.

As an initialism sss is

(us) selective service system.

As nouns the difference between sis and sisu

is that sis is shortened form of sister while sisu is strength of will; determination; perseverance; regarded as an integral part of Finnish culture.

As an initialism SIS

is Secret Intelligence Service