It is in fact an idiomatic expression. This expression can be found in Emily Dickinson's poem. Here is an excerpt:
<em>But never met this fellow,
</em>
<em>Attended or alone,
</em>
<em>Without a tighter breathing,
</em>
<em>And zero at the bone.</em>
<em />
It seems to be a reference to zero degrees (super cold). As if the character is shivering from fear with the same intensity that the character would if it was 0 degrees.
Within this context we get the biggest irony of all: They cannot find the way to please each other during the season, and their love for each other makes the other sacrifice things they like for the sake of making the other happy. In the end, they gave each other the same thing they sacrificed.
Low-skilled newcomers were supplied labor for industrialization, and higher-skilled arrivals helped spur innovations in agriculture and manufacturing. The data also show that the long-term benefits of immigration did not come at short-term cost to the economy as whole
