In Jain usage, Beej is actually a tithi — it is the second lunar day of the fortnight.

What may cause confusion is this:

• “Tithi” is the general term for a lunar day.
• “Beej” is the name of the second tithi.
• So Beej is not separate from tithi; it is one type of tithi.

In simple words:

• Ekam = 1st tithi
• Beej / Bij = 2nd tithi
• Trij = 3rd tithi
• and so on.

So if someone says “Beej is not a tithi,” that is not correct in the usual Jain calendar sense. It is a tithi name, not a different category.