In Jain practice, the difference is about how many types of food/drink are allowed after sunset:

Chovihar

• “Chau” = four
• It means no food or drink of any kind after sunset.
• This includes:

1. Food 2. Water 3. Tea/milk/other drinks 4. Any liquid or edibles

So, in chovihar, a person observes full abstinence from all intake after sunset until the next day.

Tivihar

• “Ti” = three
• It means three types are stopped after sunset, but one is allowed.
• Generally, this means:

- No food - No tea/milk/other drinks - But water is allowed after sunset

So, in tivihar, one may drink water after sunset, but not eat food.

Simple difference

• Chovihar = no food and no water after sunset
• Tivihar = no food after sunset, but water is allowed

In Jain dharma, chovihar is more strict than tivihar and is considered a higher level of restraint.

If you want, I can also explain which one is followed in fasting, sthanakvasi, or temple-based practices.