Needle in a haystack

[Lysander]

I have always thought this refers to a needle of hay rather than, say, a knitting needle or a needle and thread.

It makes far more sense that it were a hay needle. Thoughts?

 

[Lysander]

No, makes sense if it was a normal sewing needle as that would be extremely difficult to find in a haystack.

Finding a particular needle of hay would be harder.

It means a sewing needle.

Isn't that just an assumption though?

 

[Lysander]

And what is a needle of hay?

A strand of hay is also called a needle.

Needle of hay isn't even a thing.

Indeed it is.

 

[Lysander]

show me proof

http://northfacefarm.blogspot.co.uk/2010/01/nature-of-hay.html

Finally, in disgust, you drop the bucket you were carrying, unzip your coat, pull the hem of your sweater and underlying vest away from your body, un-tuck the turtleneck exposing your bare skin to the icy air, and reach up to sweep the offending needle of hay out of your clothing

I don't know where you'd find proof, but here's an example of the term being used.