Meaning/Usage: To tell someone to wait; to slow down; an expression used before providing a different point of view or opinion
Explanation: This is fairly straightforward. "Sec" in this context is one "second." You're basically telling someone to wait because you are about to say something else.
"Hold on a sec, I thought you were staying home tonight?"
"Hold on a sec, are you serious?"
"Hold on a sec. This is different from what you told me yesterday."
A. "Chip is going to draft a quarterback in the first round?"
B. "Hold on a sec. I swore he was going to draft a running back first."
A. "It's a surprise for me too, but I'm pretty sure about it."
Other Common Sentences
"Not so fast."
"On the contrary."