shiva vs shivah

shiva and shivah both are nouns.

Word	Noun	Adjective	Verb	Adverb
shiva	Yes	No	No	No
shivah	Yes	No	No	No

As nouns, shiva and shivah are synonyms defined as:

shiva and shivah: (Judaism) a period of seven days of mourning after the death of close relative

Other synonyms of shiva include shibah.

shiva (noun)	shivah (noun)
(Judaism) a period of seven days of mourning after the death of close relative	(Judaism) a period of seven days of mourning after the death of close relative