Can Someone Help Me Find this Word?

[Pat Mustard]

I think the word you are looking for is "geas"

http://tvtropes.org/pmwiki/pmwiki.php/Main/Geas

And it's definitely not a species of flying bird.

The géas is from Irish mythology, an obligation placed on a person from birth by fate which, if broken, leads to a bad fate for the person.

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Rhonda, I don't know if it'll help with your writing or not, but a geas can also take the from of an obligation that can create a conflict for your character.  By way of example, the Irish myth figure Cuchulain laboured under multiple geasa.  He was forbidden to eat the flesh of a dog, but was also obligated to never refuse a feast.  When the baddies invited him to a feast at which boiled dog was served, it caused him no end of trouble.

Boru

I imagine it did. And to add insult to injury, they were playing Another One Bites the Dust on the bagpipes.

You shoupd read, or better yet listen to, The Táin.