Sentence:  A certain factory manufactures two distinct products, ‘gadgets' and ‘<WSD>doofers</WSD>'. ... The times required for these operations, the total time available per week, and the profit per gadget or <WSD>doofer</WSD> are as tabulated: ... 
Meaning of the word marked with <WSD> tags:  An object the name of which the speaker or writer cannot remember or does not know. (from 1930s)