Sentence:  After the woman who gave me those ties left me that day, a cloud of guilt hung over me, and I couldn't shake it. It stayed with me through the night. I couldn't sleep. The woman was in her late sixties at the least, and she walked as if she carried the world on her shoulders. But she'd found a way to thank me. And I knew it was the <WSD>widow's mite</WSD>. 
Meaning of the word marked with <WSD> tags:  A very small gift or donation which, however, represents a great sacrifice on the part of the giver.