In the travel sector, "OD" is often used as a contraction for "origin - destination" - a description of a journey by its departure point (Origin) and arrival point (Destination)
Other uses
Odh or Od, a community in India and Pakistan, or their language
O.D. is one of the founders of the industrial/metal/electronic band Velcra. He has worked on samples/programming and guitars on the band's first two albums and is the main producer on their third album.
Eternal vigilance is the price of paranoia, and that's why I check my garage carefully every day. I check the garage because I figure if we get mice, that's where they're gonna get in first. We had mice in our last house ... Transgender ... Cancer is natural.