Week

 The popular Navagraha verse:

Bhānuḥ Śaśī Bhūmisuto Budhaśca

Guruśca Śukraḥ Śani Rāhu Ketavaḥ ।

Kurvantu Sarve Mama Suprabhātam ॥

Meaning:

Bhānuḥ – the Sun

Śaśī – the Moon

Bhūmisutaḥ – Mars (the son of Bhūmi, Mother Earth)

Budhaḥ – Mercury

Guruḥ – Jupiter (Bṛhaspati)

Śukraḥ – Venus

Śaniḥ – Saturn

Rāhu

Ketu

"May all these celestial powers make my morning auspicious."

The days of the week are named after the seven visible grahas:

Sanskrit

English Day

Bhānu-vāra / Ravi-vāra (Sun)

Sunday

Soma-vāra / Śaśi-vāra (Moon)

Monday

Maṅgala-vāra (Mars)

Tuesday

Budha-vāra (Mercury)

Wednesday

Guru-vāra / Bṛhaspati-vāra (Jupiter)

Thursday

Śukra-vāra (Venus)

Friday

Śani-vāra (Saturn)

Saturday

Notice that Rāhu and Ketu are included among the Navagrahas, but no weekday is named after them.

It is fascinating that many languages preserve the same planetary connection. For example, English Sunday (Sun), Monday (Moon), and even Saturday (Saturn) directly reflect the same ancient planetary tradition.

The little verse thus quietly recites the very celestial beings after whom our week is organized of how deeply astronomy, spirituality, and daily life were woven together in ancient thought.