Tithis (days) of Hindu Calendar

• 1. Padya (Pratipada)

  2. Bidige (Dwititya)

  3. Tadige (Tratiya)

  4. Chowthi (Chaturthi)

  5. Panchami

  6. Shashthi

  7. Saptami

  8. Ashtami

  9. Navami

• 10. Dashami

  11. Ekadashi

  12. Dwadashi

  13. Trayodashi

  14. Chaturdashi

  15. Poornima or Amavasya

Shukla paksha refers to the bright lunar fortnight or waxing moon in the Hindu calendar. 

Shukla is Sanskrit word for "white" or "bright".

Krishna paksha refers to the dark lunar fortnight or waning moon. 

Krishna  in Sanskrit says "dark"

kuverātmajau baddha-mūrtyaiva yadvat

tvayā mocitau bhakti-bhājau kṛtau ca

tathā prema-bhaktiṁ svakāṁ me prayaccha

na mokṣe graho me ‘sti dāmodareha​