No, Ash Wednesday is not a heathen or pagan holiday. Yes, Wednesday is named after Odin (Woden.) Yes, other cultures besides Christianity used ritual fire and some even used ritual ash. Some Hindus in India receive a blessing from ash from a sacred fire. Fire as a source of cleansing, heat, and light is pretty basic and obvious, and the fact that x culture used it does not mean y culture stole the idea from x culture.
The internet meme making the rounds that claims that fire and ash is an exclusively heathen or pagan symbol is ridiculous on its face; all cultures used fire. The internet meme claims the ashes from heathen festivals were protective in heathen culture. While it is possible that some heathens in the past did use ash for some magical or religious purpose, but if so the person who created the meme really ought to cite the source.
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