Does it have a meaning?

Yes, the word Halloween comes from All Hallows' Eve, which is the evening before All Hallows' Day, or All Saints' Day, celebrated on November 1st.

Hallow is an old word for saint, and Eve refers to the evening before.

So Halloween essentially means the evening before All Saints' Day.

Ok, thank you.

So when did Halloween originally call?

Halloween was originally called Samhain by the ancient Celts.

When Christianity spread, the church established All Saints' Day on November 1st, and the evening before became known as All Hallows' Eve, eventually shortened to Halloween.