NFL Line

In the newspaper the NFL line is given with captions “O,” “T,” and “O/U.” For example, Bears are favorite against Steelers. Both the "O’ and “T” are (is?) 2, which, I guess is how many points the Bears are favored. The O/U is “(40 1/2).” What is that?

The O/U is the over/under. It’s a bet on how many total points are scored.

So, if the O/U is 40.5 and the score is 21-14, you should bet the under (21+14 = 35).

I’m not sure what the O and T stand for but possibly opening line and current line.

The line is indeed what is also known as the spread - the amount by which a team is favored to win (or lose).