It’s just over a week until the kids put on their skeleton costumes, grab their swagbags and frighten the life out the locals at Halloween. Or is it Hallowe’en?
The event was originally known as All Hallows Even, later simply called Hallow Even. Strictly speaking, Halloween is a contraction of this and should be written as Hallowe’en (the apostrophe shows that something - in this case the v – is missing).
However, with many words, the shortened form eventually becomes the norm . For instance, we no longer use an apostrophe for fridge, phone and flu even though these are short forms of refrigerator, telephone and influenza respectively. As they have become “everyday” words, we don’t use the apostrophe any more.
While grammar pedants (er, that’s me) might prefer to use the apostrophe as a nod to its original meaning, you could equally argue that that the name has changed over time, making the apostrophe redundant.
So I think the answer is to feel free to choose one or the other…but be consistent.