pillar of Islam vs sawm

pillar of Islam and sawm both are nouns.

Word	Noun	Adjective	Verb	Adverb
pillar of Islam	Yes	No	No	No
sawm	Yes	No	No	No

As nouns, sawm is a hyponym of pillar of Islam; that is, sawm is a word with a more specific, narrower meaning than pillar of Islam:

pillar of Islam: (Islam) one of the five religious obligations accepted by all Muslims
sawm: the third pillar of Islam is fasting (primarily during the month of Ramadan); Muslims abstain from food and drink and gambling and all sensuous pleasures from sunrise to sunset during Ramadan

Other hyponyms of pillar of Islam include shahadah, salaah, salaat, salah, salat, zakat, hadj, haj, hajj.

pillar of Islam (noun)	sawm (noun)
(Islam) one of the five religious obligations accepted by all Muslims	the third pillar of Islam is fasting (primarily during the month of Ramadan); Muslims abstain from food and drink and gambling and all sensuous pleasures from sunrise to sunset during Ramadan