Actually what you meant to say, 6zeva9 & D-Best, ist that the term "Halloween" is derived from those old English words, D-Best got it right. But this derivation does little to clarify what the meaning is here.
Hallows are venerated objects or icons, you know, the very thing forbidden by God in form of but not limited to the golden calf ^^. Anyway, the word denotes the (material) attachments which tie you to the material world, so the enlightened, spiritual meaning of All Hallows Eve(n) as in the evening/ end of the attachments is, logically: Detachment.
The "dark side" really loves this holiday because "the destruction of the old world" meaning a world under god's rule, is an important prerequisite for a new (ungodly) world with its own artificial rules. New world order stuff if you will, Lucifer's dream.
Hallows are the Saints. Halloween is the day before All Saints' Day, or All Hallows' Day. It has nothing to do with Lucifer or the destruction of the world.
Let an agnostic ask you one question: what tf are you even talking about?
Then, agnostic, which derives from greek and is understood as 'one who does not know', heed, if you will, the words of a gnostic who does know.
As I said: Hallows are venerated objects (which is true) or
icons as in paragons or idols
which can be a person or other and a representation of a person or other, be it a picture, image or sculpture.
I talked about the difference between knowing what word(s) another word comes from or what other words have a similar meaning and what it really means. For example: Somebody asks what 'satan' means, gets an answer 'the devil ...or lucifer'. The answer is not completely wrong, but really it is the answer to another question, something like 'what other names of the guy do you know?' The right answer is, satan (literally) means 'dark lord' or 'lord (sa) of darkness (tan)' or in one word 'shadow'. To this day, German has the word 'Schatten' which has the same root, meaning and almost sounds the same. Many people today know that 'lucifer' carrys a meaning to the effect of light-bringer or -bearer. It means something different and can point to the same "guy" -- but lucifer can also aptly describe the sun as in (day-)light-bringer or the brain as in bringer of the light of knowledge and reason.
Now: what is the world, what does it mean? Does it mean the earth? No. The world is everything we built on the planet, our buildings, structures, systems, thinking patterns. This is the stuff destroyed in the end times and on an individual level have to be destroyed but better, let go willingly so you can find your way home, back to God.
In this way, All Hallows Eve has everything to do with Lucifer, as he was the first one to fall, his dark side, his satan/ shadow becomes the icon for dark-siders while the light-siders adore the 'morning star', 'the light of the world' as soon as he successfully mastered Halloween, the end of all attachment to the material (ego), asks for forgiveness and sacrifices his mortal form to the well-being of those he loves.