talcum vs talcum powder

talcum and talcum powder both are nouns.

Word	Noun	Adjective	Verb	Adverb
talcum	Yes	No	No	No
talcum powder	Yes	No	No	No

As nouns, talcum and talcum powder are synonyms defined as:

talcum and talcum powder: a toilet powder made of purified talc and usually scented; absorbs excess moisture

talcum (noun)	talcum powder (noun)
a toilet powder made of purified talc and usually scented; absorbs excess moisture	a toilet powder made of purified talc and usually scented; absorbs excess moisture
a fine grained mineral having a soft soapy feel and consisting of hydrated magnesium silicate; used in a variety of products including talcum powder