Answer

In Jain usage, it should be written as Ayambil — with the letter “k” not required.

The commonly accepted English spelling is:

• Ayambil
• Sometimes also written as Ayambil Tap

Explanation

“Ayambil” refers to a Jain tapasya in which one eats simple, tasteless food once a day, without items like spices, oil, ghee, milk, curd, sugar, green vegetables, etc., depending on tradition and guidance.

So if you are writing it in English, “Ayambil” is better than adding a “k”.

Takeaway

Use Ayambil. The letter “k” should not be added in the usual spelling.